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Discussion Starter #1
Hello All

It's been a loooong time since I introduced myself. Been busy with an 86 928, Jaguar XKR that went for a swim in Texas, and an XJS that I've been getting ready for the road - for like a million years.

I think I'm at the point of being able to start messing around with a 1986 Honda Goldwing gl1200, 26k, that's been sitting for years. I want to and will strip it down to bare basics and make some sort of racer. Am not clear on that vision, yet... As of now it runs, cools, idles sweetly - all plastic has been removed.

I have been watching vids and reading about the M-Unit that will serve as my basis for wiring. Lights, horn, key etc are not such a worry with the M-Unit. BUT,,, and there's always a but,,, in all you all's experience (deep bow) are there things I need to know or be thinking about when it comes to ignition and ignition systems - charging - starter relay/solenoid - stator - rectifier/regulator,,,, or is it all pretty much straight forward? Will the M-Unit work predictably with the Goldwing charging and base of it's electrical system?

I have a lot to learn from you all and this is the beginning of a long road for me with this thing. I really really appreciate any and all guidance offered up.

Thanks Much
 

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From my experience the M-unit is unnecessary for what you are doing, your stock honda wiring is completely adequate. I have been going down this road my self because I have a VW engine in a BMW R69S chassis that requires a complete from the ground up wiring harness and even I am on the fence about the m-unit.

Things the M-unit does not do:

  • Simplify your wiring harness. A lot of people think I'm going to build this super stripped down racer so all I need is a super stripped down wiring harness, but at the end of it it does not reduce the amount of wiring, nor does it substantially change the wiring diagram of the stock bike. You don't have to take my word for it, revival cycles has more than a few video tutorials on youtube and they say the same thing in at least 2 of their vids
  • provide secure connections. The m-unit uses screw connectors, which aren't exactly the best way to attach wiring in a wiring harness
  • The accessories like their handlebar switches (not the M-button) are poorly made and ground out easily. A lot of people like running the M-unit because they want to spend a lot of money on custom handlebar switches their bike's stock wiring harness wasn't meant to work with (e.g. have high low and off headlight control all be controlled with one momentary switch and 2 wires) and need a controller to provide some of the functionality. Of course the easiest to adapt are motogadget's own switches because they are plug and play, but their design isn't super great and a lot of people I have spoken to who have used them have had problems with the switches grounding or shorting in the housing. This isn't a wiring or an m-unit problem per-se, it's a design of the housing for the switches problem, and you can avoid it by using other controls, but most people pulled in by the M-unit's sales pitch are usually pulled in to buying the switches and the m button and other stuff they may not need.
  • Using the M-unit makes it easier to diagnose, but makes it hard to repair if the unit itself goes bad. Motogadget is full of backorders and frequently out of stock on the unit, and few if any places keep them in stock on their shelves. It is rare but not unheard of for a unit to go bad, and if you are stuck broke down on a trip, a bad unit can mean the end of your trip.
that said, here are some things the M-unit does really well:

  • It adapts your bike to a modern Can-bus electrical system which makes diagnostics and troubleshooting much easier. The M-unit Blue lets you even use your phone as a can bus reader to work the unit. It also eliminates the need for fuses as it uses solid state re-settable breakers, so you don't have to carry around spares anymore. even on the most basic unit, it's nice to be able to look at the front panel and see the yellow illuminated LED showing which circuit has a fault.
  • It adapts an alarm to the bike and also allows keyless RFID ignition. The unit has a motion gyro in it and if the bike is moved without the keyswitch being on it flashes the lights and honks the horn. It also makes it really easy to have a modern keyless ignition if you have the M-unit blue and I believe it even comes with the key fob. I think you can also start your bike from your smart phone.
  • It centralizes the relays, fuses, and junctions. You still need wires running to those things so it DOES NOT reduce the number of wires your wiring harness, but it does move it all to the same location. It also eliminates the need to buy a new flasher unit if you are going to run LED signal and brake/taillights as well as other things like resistors. It also eliminates the need for accessory controllers if you want to do things like change your signal rate, or use one momentary switch to perform several functions.
To answer your ignition system question - you treat your ignition and charging system as a standalone circuit, and then connect it to the m-unit for power where it says ignition. Even on your stock GL wiring scheme, there is 1 power supply wire that connects to the ignition switch circuit and basically you plug that into the m-unit instead of directly to the power circuit.

If you want my opinion (and I assume you do because you are posting it on the internet) an M-unit is a waste of money for you right now. You have a bike with an intact stock wiring harness and diagrams and even though it runs, you have no miles on it and don't know what's about to fail. Having a stock wiring diagram is way better than having an m-unit, and much of the cool diagnostic functionality can still be performed with a multi-meter and a knowledge of how to use one. Later on when the bike is sorted out and everything functioning as should, then you can rewire from the ground up with an m-unit and all new electrical components and have it make a little more sense - but an m-unit will not solve other problems for you. It won't fire bad coils, it won't fix bad grounds, or breaks in wires, it won't magically heal bad stators, and it won't make a bad bar control switch start functioning again. It isn't a solution to anything wrong with your bike - it's an accessory when you want to add new functions, and you can't add new functions on to a broken system and you need some miles on your bike to know for sure your system isn't broken.

If you are not changing literally everything from the bar controls to the idiot lights, there is no real monetary or time value to using an m-unit to power stock units. If you were building a show bike and needed 1 wire from the handlebars and needed to hide as much as possible, then the m-button and the m-unit makes a lot more sense, but show bikes don't get ridden and usually have unlimited check books - also the m-button doesn't "simplify" the wiring, it just lets you hide it all inside the handlebars instead of inside the frame.

Let me give you two case scenarios from my own shop: In my shop I have two bikes I am currently working on. 1 is a stripped down 1971 cb750 K1 and the other is a 1968 BMW R96S with a 1968 VW beetle engine shoved in.

On the honda, I am changing the lights, the signals, but the switches and ignition system is staying the same. It would never occur to me to spend near $400 on an m-unit for this bike, even when I am upgrading the fuse box to blade fuses, the signal solenoid to an LED friendly one, and the REG/RECT to solid state. For one I know all the wiring color will be the same, and I can use the stock wiring harness as a road map, second I can find parts at most auto parts stores or bike shops. The only things the M-unit brings to the table is an alarm and the ability to change the flash rate of the signals, and $370 is too precious for me to bother for those functions I can live without. It's more important to get this bike to run stock and then upgrade where there is a need, an m-unit is a waste of money.

On The BMW/VW I have a honda bar switches, into xs650 gauge cluster, into the BMW main harness, into the VW engine bay electrics. Some circuits walk through 4 different wire colors, and there are breaks, junctions, and disconnected wires everywhere. The bike obviously needs a ground up wiring harness. For this project the M-unit makes sense because I am replacing nearly everything electrical on the bike and none of it is stock. Seriously, even the idiot lights and gauge lights are going, and it is all being custom wired. Generic wiring kits for dune buggies that use quality connectors are $100-200, putting my total supply costs are around $300-$400 by the time I am done with new connectors, LED flashers, starter relays etc. Conversely I can buy an M-unit Blue for $380 and a wiring kit for $80 from Revival and be into my wiring for $460, with all the cool added functionality. For me the price differential of $60-$160 makes a lot of sense, it's a bargain for the alarm and the ability to diagnose with a smart phone. Even still, I am working through my garbage setup now to make sure all the components work before I pull the trigger on a full rewire so I am not banging my head against the wall thinking I have a bad unit when it's a bad coil or a bad regulator, or even a bad generator.

make sense?

IIRC you are in NYC or close by right? Go down to Lurkshop in Brooklyn and ask Ross to show you the ins and outs of the m-unit.
 

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Discussion Starter #4
Thanks Gee and CaT...

The bike has a staggering amount of wiring as is. I want most all of it gone. Gee, your super detailed (thanks) post gives me pause,,, but I think I will need and want a central point (M-Unit or similar) to start, from near zero.

In working on the crazy electrical systems of a Jaguar XKR, the cleaning house of wiring is not an option. All electrical connectors are needed,,, using the electrical diagrams identifying where and which etc, makes sense... On this bike, thru each of the OE connectors once stripped down, many of the OE connectors will have many lines/ports/plugs that go unused. The OE loom is huge (more than one) and I would do what, open them and remove the wires no longer in use? That's too much, I think. The only thing that's seems to make sense for me, even if it just to not have to deal with the spaghetti,,, is to do away with near all,,, and start there. Huge numbers of lights alone, in this thing.

It's good to know and hear about the stand alone basic charging system. This is good.

My budget is super tight and my first go at this I don't intend to be the last. I'll go back and install better switches at the bar, lights and components, over time. The Rivival components are not an option. Toooo costly. Just the Unit as the starting point for the rewire. That's all the money I'm giving them dudes.

Like the BMW everything is going. Starting from zero... Which is ok... If it is possible,,, I do plan one figuring something out with the core of the digital display, the tach and speedO, gear, fuel level, temp and a few other things are all in there. I'm hoping I can power it, work with the sensors and wire all them things as are. We shall see.

For me, I think the M-Unit still makes sense. But still, I have a lot to learn.
 

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Easiest and cheapest is likely modifying the existing harness, take out what you don't need and reroute as you require. Learn from it and save your money for a project that is worthy of building a custom harness.
 

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I totally rewired a 1981 yamaha xs850. I found it way easier to utilize the stock harness and remove what I didn't want than to wire up a brand new wiring harness. I mean there just things like the charging system and several other subsystems I would rather not have to rewire and find new connectors for.
That is assuming you have a healthy stock harness and take the time to understand the wiring diagrams.

It was easily one of the most mentally taxing things about the racer build for me. YRMV...
 

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Discussion Starter #8 (Edited)
I totally rewired a 1981 yamaha xs850. I found it way easier to utilize the stock harness and remove what I didn't want than to wire up a brand new wiring harness. I mean there just things like the charging system and several other subsystems I would rather not have to rewire and find new connectors for.
That is assuming you have a healthy stock harness and take the time to understand the wiring diagrams.

It was easily one of the most mentally taxing things about the racer build for me. YRMV...
Hey JC... All I can think after reading what you've said, is yes! Mentally taxing - would and will be for me as well. Electrical is not my strong suit, if I have one, haha

The bike sat for years and in less than a couple of hours,,, excluding the time it took to remove 4carbs, jets cleaned and reinstalled, it took just a bit to get her running, idling smoothly and - after replacing thermostat and temp sensor - just a bit more to get cooling system and fan running rightly. Super easy compared to some of my other,,, "projects"... I'm excited about this...

I will take and post some photos of this thing. Huge amounts of wiring. If I were to just rig switches on the bar,,, lights, ignition switch/key, coils - the basics - what would be left over of the OE harness,,, it's plugging sitch,,, would a jumble. I would have large plugs with maybe 3 or 4 active wires, with 12 blanks.

With the M-Unit or similar what I am really wondering is if, BEYOND the connections the M-Unit handles built into it's design - would an 86 gl1200 Goldwing even run? If not,,, what else do I need to be thinking about? Are there run dependant systems in this thing MORE than the basic wiring? What have I not considered? An electronic or analog style ignition system - computerized? I'm leaning toward (NO) theres not but to sleep better at night,,, and before diving in,,, I was searching for some reassurance, lol... There must be a timing element, right?

Anyways, it's a MESS of wires running around this thing. It seems, and I could be wrong, that it would be a beast to remove what I won't need, and leaving what I will.
 

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It's mentally taxing for anyone who doesn't regularly work with electricity. But it's more about time invested than figuring out complex systems.

Your GL comes from an era where honda was starting to not only standardize wiring, but also offer plug and play accessories where all you had to do was find the empty plug in the harness to add things like a stereo and extra gauges. Prior to the block connectors, everything was male/female bullet connectors

A good beginning approach to this, and something I did for my own project, is to get a wiring diagram for your bike, import it into photoshop, and then start erasing all the wires that do not connect to the ignition system or charging system. Don't erase the things themselves like the turn signals - just the wires that connect those things to the bike. Do it on a copied layer so that you can bring up the original if you need a reference. Then in another copied layer of the one that you just made of just your ignition system and charging system, erase the fuse box and turn signal flasher, and put in the M-unit and start drawing the wiring to the m-unit and the ignition. At the end of this you should have 3 layers: the original wiring diagram, the essential wires from ignition and charging that you need to keep from the old harness, and the new wiring diagram for your M-unit. That should cover you for the most of the "mentally taxing" portion of the wiring - creating the map. Once you have the map it's a matter of following it.

What you will see from this exercise is how little the M unit changes. For instance in a normal headlight circuit you have a three position switch with three signal wires (off/low/high), and two wires and a ground going to the headlight. With the M-unit, you still have the 2 power wires going to the headlight from the m-unit, but only one signal wire and one button to power the headlight, where the functionality is determined by how you press the button programmed into the m-unit (quick push - flash to pass, hold for 1 second switch from low to high and vice versa, and hold for 3 seconds to turn on and off). Same thing with the turn signals - you have 2 signal wires and 4 power wires and a flasher relay for the blinkers, and a separate power wire for running lights, and a separate power and signal for hazards (if your bike has them). With the M-unit, you still have two signal wires and 4 power wires, but the relay is built into the M-unit, the running lights use the power wires instead of having a separate running light circuit, and instead of a separate hazard lights signal wire, you can program it to flash the hazard lights when both turn signals are pressed eliminating the need for a separate hazard signal wire and button. the unit can even vary the power sent to the bulb over one wire so you don't need a dual stage bulb and separate power wires for a brake/taillight.

That's the advantage of a can bus system in general - instead of requiring separate signal wires and separate power wires, it uses time and software to differentiate the different switch inputs, and variable power feeds to run things like taillights and brake lights. at the end of the day you still have the same number of circuits, just the circuit itself gets less "complex". This is why I said if you are going to do an M-unit you should do it at the same time as you change the lights and controls, with your stock controls you aren't using the M-unit to it's full potential, you are just using it to put all your fuses and relays in the same place, and when you eventually do make the change, you are going to have to wire it all again from scratch.

For me, I have started to collect the lights and switches first, and once I have all the ones I want to use I am going to buy an M-unit and begin the from scratch wiring. But then again, my bike doesn't run and even if it did I couldn't ride it in it's current state. If your bike runs and is ride-able, you probably want to keep it that way while you modify other things like bodywork, seat, foot controls, brakes, tires, suspension, etc so you can test your mods and see how you like them.
 

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It's mentally taxing for anyone who doesn't regularly work with electricity. But it's more about time invested than figuring out complex systems.
Maybe... I think going from reading and understanding the wiring diagram to dissecting an existing wire harness is another level up. 1/2 level at least. Then taking that skill and actually modifying the harness for an m unit or truly simplifying it is another level.

I can wire a tach, install a shift light, wire the battery through a relay directly to the coils, relocate batteries, install aftermarket fuse blocks, etc. This is all simple. Even on the modern bikes, bypassing clutch switches, side stand switches, removing switchgear without setting the ecu in lockdown mode, I've all done for my track bike. But I'm telling you trying to dissect out and then intelligently modifying an old wire harness from a fairly straightforward wiring diagram was tedious and painful for me.

The wiring diagram/harness had some interconnected systems that took some time to decipher (example, everyone has a simple idea of the charging system wiring, but stock harnesses have connections for pressure switch grounds and headlight circuits spliced in). Not to mention I found a couple literal errors in the wiring diagram itself- a factory manual, not Clymers or Haynes.

It's not impossible, maybe it's not even super hard. Mentally taxing is the best way I can describe it... I don't know, your results may vary. What I did was remove all the wires for the stock lighting from the harness and build a new subharness to handle the simplified lighting, install an upgraded regulator rectifier, remove the dash wiring and build a new subharness for a race tach and basic idiot lights, shift light. oil pressure and temp gauge and sensors. Pretty standard stuff for a racer build.


As for the OP, I think the answers to your question are in your wiring diagram for your particular bike. I don't believe the M-unit replaces your entire wiring harness. Subsections like the charging system is separate from what the m unit handles. I kinda think of the M-unit as a glorified fuse box with a nod to the ignition circuit... So if you add an M unit to your existing harness, you are probably adding a ton more wiring. Far from "simplifying" things. For it to be "simplified" wiring, you first need to tease out of your stock harness all that the m -unit can't handle. Yes, the timing computer, cdi, wiring to the coils, charging system, sensor power and grounds...
 

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Maybe... I think going from reading and understanding the wiring diagram to dissecting an existing wire harness is another level up. 1/2 level at least. Then taking that skill and actually modifying the harness for an m unit or truly simplifying it is another level.

I can wire a tach, install a shift light, wire the battery through a relay directly to the coils, relocate batteries, install aftermarket fuse blocks, etc. This is all simple. Even on the modern bikes, bypassing clutch switches, side stand switches, removing switchgear without setting the ecu in lockdown mode, I've all done for my track bike. But I'm telling you trying to dissect out and then intelligently modifying an old wire harness from a fairly straightforward wiring diagram was tedious and painful for me.
I'm just trying to be positive. All this stuff can be figured out with enough time, the problem with time is having enough enthusiasm to get you through the 3+ months your bike is torn apart in a corner with no wiring. It's not like we are trying to go to the moon with manual switches, It's a motorcycle with a lot of the same components and a knowledge base. If you keep going eventually you can come out the other side....if you don't get so frustrated first you set it on fire or whole sale it on craigslist.

That said there are guys who can just look at this stuff because they work with it every day and it makes sense to them. I have a buddy from high school who fixes airliners, and a couple years back we were tying to get my GTO started with no spark. I am sitting there with a multimeter working my way through the wiring harness for at least 45 minutes before he grabs an old honda turn signal off the shelf, makes it into a continuity tester, tests three wires, tells me my MSD digital six is bad, rips it out, rewires the ignition, and starts it. It took him 10 min. Would I have got there? sure probably in another 15-20 min and then another 15 to remove the box and reconnect the ignition wires. I'll probably not be anywhere close to his skill level because he's had training and a metric ton of practice, but it doesn't mean we can't get to the same destination.

The point is - don't get intimidated. Make a plan, come prepared, and expect it to take time and be flexible enough to change your plan if needed.

I can agree it is mentally taxing. I'm right now trying to figure out how to wire a 1960's Italian 6v ignition switch into the vw/bmw, and all the wiring diagrams are in italian or spanish (benelli 250 headlight and switch). I've been on it for 2 days and I haven't figured out yet which wire would be the ignition signal wire into the M-unit. I also have no idea what the "D/B" switch on the underside of the light does or what to do about the fuse that is mounted right on the circuit board of the switch (which the M-unit would make unnecessary). I also can't seem to get power to the ignition system on the bike by directly powering the coils, which means I am checking every component to make sure it works - tedious is probably the best way to describe it and what makes it mentally taxing for most people.
 

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Discussion Starter #12 (Edited)
Gee and JC,,, you guys are amazing. Thank you. Lots of the ideas that both of you touch on are the things I have floating around in my head.

I agree, stay positive (not weirdly) and given time, these things can be done - even if the learning curve is steep... I'm in no rush and not afraid to make mistakes OR learn how much I don't know.

My vision for this bike is completely stripped down. As basic basic as possible. The bike is so meaty,,, lots of metals,,, once covered by plastic... I like it's shape as far as it is stripped down down so far. How it sits. It's sound. I want there to be a 'darkness' about it,,, kinda ominous. In that, the fewer bells and whistles, the better.

Yes,,, Honda charging system intact - replacing some of the old wires or rerouting them for sure... Beyond that, I feel the best option for me (and my vision) is to start from scratch,,, or near scratch with most other things. If I find that conveniently,,, there are wiring harnesses in place that make it so I don't have to replace or rewire, I will use them.

The Goldwing comes with a digital display (like below). The entire dash has 3 LARGE wire looms with 3 separate large connectors going into it... I may need ONE of these looms and one of these plugs,,, the one that feeds the digi display - but I don't need or want them all....?


The faux tank I will use (I have 3 to experiment with),,, I will cut them and fiberglass them into a shape to better fit my vision. I will remove the digi display from the surround and fiberglass a new frame-up for it and glass it nicely in place on the faux tank. I will need to wire it, power it, and such - probably with the OE plug - that makes sense... But,,, a small neutral light, high beam light and a few other items will be rewired. I don't need those huge looms and plugs for that- while temp, tach, speed, gear, milage and trip will remain in the digi display,,, but will need to wire all this.

I will drill and feed wires thru the bars,,, where I can.

Beyond this is lights front and rear, a horn, kill switch,,, all these things are handled nicely by the M-Unit... "Revival" on YouTube have great mapping and schematic planning ideas (like you said Gee,,, thank you) which to me,,, make clear the benefits of using an M-Unit like device to "center" and land the plan for wiring. Much benefit,,,, especially for the novice, can be had by using the framework as supported by the M-Unit. At least that how it seems to me.

The M-Unit has an AUX,,, then, in videos I've seen, powering several components off a 12v power strip of sorts... What I'd seen is that the M-Unit makes a keyed "hot" wire possible to rig a line that will power a hand full of things with a simple turn of the key - ignition on... That many components can work off and be run on that "hot" wire. Just made sense to me. Sorry,,, I'm at a loss for all of the correct terms.

I will send some snaps... This thing is LOADED with wires and the idea of cutting into all of those looms and figuring out and tracing them all,,,, the idea of it makes my hair hurt, and I have long hair, lol...

Again. I could be completely wrong, but to me, on a Goldwing that must have 1-2 miles of copper on it stock,,, tearing it down and starting from scratch seems to be the only way to go.
 

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the issue my experience leads to is that honda wouldn't have put all that shit on there if it wasn't necessary, and with that dash and it's pre digital basis i can imagine just the kind of nightmare required to run it. thinking you can make it less volumous is a bit of a fantasy imo, unless you're really, really good at it. and know exactly the ultimate effect of removing stuff. that's the issue - getting to the end and finding that something you discarded some time ago is fundamental to what you want to do.

good luck with it, but.
 

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Discussion Starter #15
the issue my experience leads to is that honda wouldn't have put all that shit on there if it wasn't necessary, and with that dash and it's pre digital basis i can imagine just the kind of nightmare required to run it. thinking you can make it less volumous is a bit of a fantasy imo, unless you're really, really good at it. and know exactly the ultimate effect of removing stuff. that's the issue - getting to the end and finding that something you discarded some time ago is fundamental to what you want to do.

good luck with it, but.
Exactly... Was kind of the main jist of the post and question... In the Goldwing setup what systems,,, where how and why - are not compatible with the M-Unit and/or removal of items and components (wiring basically) in a quest for electrical simplicity...?

What HAS GOT to stay?

Folks have said stand alone charging. Agree!
Anything else integral to normal functioning?
 

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Discussion Starter #18
In the first comment,,, I thought I heard pre digital,,, in the second, digital... Which is it?
 

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it is a digital display, but i expect the inputs and logic are analogue. these days dashes are usually run with can bus from the required ecu. back then it wasn't. i would think that will make it much more involved. probably wrong, and just making shit up.
 

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See this is where you need a Goldwing forum with people familiar with your exact year and model bike.

i have no clue how Honda did its digital dashes, but I do know that on other digital dash vehicles from the 1980's the signal sensors are the same analog electrical sensors that powered old fashioned dial gauges and the dash had the circuit board. I caveat Honda here because at the same time your bike was rolling off the assembly line in marysville Ohio, Honda was also producing a fuel injected turbo motorcycle that was computer comtrolled. So it's entirely possible your bike has a computer outside the cluster - in which case yeah you really can't remove anything related to the computer. I just don't think any of us know.

The m-unit cannot replace the functions of an ecu, program module, or anything that collects signals in a computer like fashion, it can only provide power to that thing when the ignition is on.
 
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