Fog diode mod causing BCM SHORT and no warranty coverage

[adam.busch]

The first issue is the puddle/domelight's. I first noticed the issue when the puddle lights were flickering when the unlock button was pushed or the door was opened. Also, the interior dome lights would not come on when the door was opened. I've pushed the overhead switch to the on position and sometimes they would flash on quickly and shut off, but most of the time not come on at all. The dome lights come on when the individual buttons are pushed, but not at all with the overhead switch. Anyone know where the fuse is that controls the overhead switch?

 

My second issue is with the left turn signal. On the DIC I got a turn indicator failure for the left rear. The indications are with the blinker activation, the mirror/dash blinker lights will flash normal for about three seconds and then pulse quickly, followed by DIC message. *edit* Brake lights (left) also don't activate.

 

I took the truck in today and got it diagnosed. The diode mod, performed exactly like the steps in this forum, somehow shorted out my BCM. I can't believe that would have done it, considering several other things that BCM controls work without issue. Well, new BCM and programming repair will cost one $675 dollars, all because I forgot to take out the damn diode before going to the dealership. Hard life lessons.

 

sidenote: I also performed the footwell lights modification and I'm certain this somehow factored into the equation.

 

I just removed the bcm and there are no chared areas or visible broken solders. If the bcm shorted out, wouldn't I be able to see something on the circuit board? Can any trained eyes spot any areas of interest where I can snap a closer photo to post.

 

With everyone who has had zero issues with the diode mod, I find it hard to believe this is the case. I think they saw the mod and blamed it all on that right away.

 

Should I even take it as far as to say per the magnuson warranty act, in order for them to decline warranty coverage, they have to prove the diode caused the failures?

 

Financially, what could that lead to in further costs for me, or will they not want to hassle and potentially just fix it? The entire BCM looks unaffected

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[newdude]

Your modifying of a wiring circuit to alter its function would not be a Mag-Moss deal. That is more pertaining to say, a Magnaflow catback, a Volant intake, aftermarket wheels, tires, etc. You have altered a wiring harness.

[adam.busch]

This is the diagnosis. With that wording in my file, will that affect future warranty work?

[newdude]

This is the diagnosis. With that wording in my file, will that affect future warranty work?

 

For 3yr/36k issues? Most likely. Powertrain may be unaffected. Over 30 DTC's? ...Wow...

[Thomcat]

Could be used as a reason to void all ECM networked electrical system and vehicle accessories containing solid state components.

 

All electrical systems switching/monitoring are controlled by the ECM within its CPUs internal pathways smaller than a human hair and susceptible to external damage not visible on the external circuit board. A momentary short caused by touching the diode or a wire to the wrong exposed pin(s) even for a fraction of a second could cause such damage. All the GM electrical accessories I've installed in my vehicles Silverado sports bar, bed lights, Camaro fog lights, etc. have always included either a new or replacement wiring harness to add the accessory or function, never splicing into existing wiring or messing with exposed pins.

 

Shouldn't affect mechanical components or drive train hardware.

 

Unfortunately, other than the remote chance of finding a good a used ECM from the same model, year vehicle with the same accessories which should be plug and play any replacement part you purchase will require dealer reprogramming anyway. So, you might have to pay the devil his due and have the dealer replace and restore the warranty on future electrical work. Wouldn't drive it too long in it's present state because there may be other engine control circuits within the ECM's CPU that were weakened or compromised which could fail at any moment and leave you stranded.

[TxTruckMan]

People don't seem to understand the complexity of these newer vehicles. They are now integrated systems controlled by application specific "computers". You modify something and it could easily cause a ripple effect. I'm sorry about your problems, but it's the risk you take with custom mods.

 

Like the previous poster said, I'd probably bite the bullet and have the dealer make the repairs back to stock if they'll guarantee that they'll honor the warranty in the future.

Edited June 14, 2016 by Black03Yukon

[CounterMeasure]

As a software developer and electrical engineer, in layman's terms, a IC doesn't have to let the magic smoke out in order to fail. I've seen countless MCUs and other ICs act wonky due to internal shorts and resistance that can only be detected on an o-scope or other test tool. I once spent about a week chasing an intermittent code bug that turned out to be a bad batch of MCUs enabling output pins even with the software disabling them.

 

The purpose of the mod is to allow one circuit to turn on another. The use of a diode here is to cause current to flow in one direction only; one circuit turns on the other, but does not allow the inverse. However, not all diodes are created equal in terms of efficiency in doing that, especially for initial surges, so leak back can cause havoc. Not saying that's what happened here, but its the first thing that comes to mind.

[TxTruckMan]

True. And don't forget that you're now driving two circuits on an output that was only designed to drive one. We don't know the specs on the driver, but it could easily be a contributor.

[adam.busch]

Thanks. All good responses. Certainly will be returning for repairs. No mention was ever said to me about voiding a warranty, however clearly a concern. I won't be performing the mod again, considering I could have bought some really good lights for a better improvement than the simple fogs provided coming on with highs.

[15 Z71]

Yep. This is why I won't do anything but drive mine. I even have my dealer do oil changes. This way, if ever a problem I can tell them your the only ones who have touched it. Good luck!

[ricker6869]

Its a risk we all take when we mod or tune. The saying goes...you gotta pay to play !. I along with many have done these mods...no issues yet..I did not use diodes..just jumper wires. I feel your $$pain..but the true mistake was not removing the diode before going in for electrical issues. Goodluck.

[Britt Lifsey]

Its a risk we all take when we mod or tune. The saying goes...you gotta pay to play !. I along with many have done these mods...no issues yet..I did not use diodes..just jumper wires. I feel your $$pain..but the true mistake was not removing the diode before going in for electrical issues. Goodluck.

And people here complain that the dealers are lying, thieving, good for nothing jerks...

[scott.moody.9401]

it would be simple enough to come up with a low cost driver module to do the heavy lifting of driving the extra relay. Maybe something like a 2N2222, config it like a saturated switch, power and ground, an enclosure...

 

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[Willshire]

Wait. You soldered a diode on to a $600 board just to have fogs when your high beams are on? I have never heard of this mod and judging by your experience i do not intend to perform. Light output is just fine for my wallet. lol. Thanks for posting this warning to those of us who had not heard of this.

 

A really nice LED bar behind the grill for that money!

[cbrsilv15]

First, a LED bar is illegal to have on while driving on the road. The diode was never soldered on. It simply pushes up in the harness plug. There's a few threads on here about it. I've had mine in with no issues.