Bizarre Electrical Issues (2012 Silverado)

MrRotten · June 13, 2020

I am new to the forums and hoping someone may have seen this or run into this before. I own a 2012 Silverado LTZ Crew Cab, 5.3L, 2WD, 102K miles, Factory radio with a harness plug for a an amp for subs. Electric drop down side steps. LED headlights & fogs. K&N Nighthawk Intake. Battery is less than a year old but i'm in Arizona so batteries get wrecked yearly.

I recently took my truck to my local DIY car wash place where I always go. I washed my truck like normal and dried it off like normal. I did not spray engine bay, just the front grill area inward but not heavy. I don't usually use my AC but I'm in Arizona and it was about 109* outside. When I was leaving the car wash I kicked my AC on so I wouldn't mess up the clean windows from rolling them down. I proceeded to leave and as I was coming to the stop sign before making my turn and my truck's idle started to drop, truck kinda sputtered, the battery voltage dropped, the stabilitrak light, traction light, ABS light, all kicked on. The radio shutoff and turned back on. The AC shut off and turned back on, but switched from recirc to fresh. I turned the AC off and then back on again and continued to drive home. It did it a few more times so I swung into the gas station to park and see if it would do it while i was sitting there. Nothing. So back on the road again, turned my AC on and hit the next light, and it did it again.

I changed my oil today (6/13), I cleaned my K&N air filter last weekend. I took a trip to Lowes this morning to see if it was still doing it, and sure enough it was. The photos are attached of it doing it in the lowes parking lot before I left. I rolled the windows down, turned the AC off and cruised home. It didnt do it again. So I am thinking the AC is drawing a huge amount of power from the system when I run it, or my battery is done for. Any helpful feedback would be appreciated.

MrRotten · June 14, 2020

Also I put on my Kobra OBDII scanner and ran two apps with zero results. No code firing and I was able to duplicate the same result. I will start with having the battery replaced first and see what happens after that. My battery did drop to damn near 5 just driving around my neighborhood, speeding up and slowing down to a complete stop.

Carissa · June 15, 2020

So i am having this issue with my 2017 silverado and the dealership has tried multiple things. They won't listen to me about what is really is. Check out G218 electrical issues on youtube and google.. You sound in the same boat as me.

goooodluck.

riverbanks · June 16, 2020

Yup,power demand,weak circuit, check all grounds, including neg. Bat. Cable

sefiroxx · June 16, 2020

2 suggestions.

1) ac off, fan on. Do the symptoms come back? If yes, then water got in the air intake to the blower motor. If not

2) compressor clutch coil circuit probably shorted out. Probably was a tiny, low amperage short but the introduction of water might have allowed plasma arcing and this increasing the dinosaur
Amperage flow. Pull the fuse, relay for the clutch and see if the symptom remains

MrRotten · September 24, 2020

I am posting an update. I did a battery exchange at the auto parts store shortly after posting about the issue and it seemed to resolve my issue. Fast forward to 3 weeks ago the issue restarted.

Took the truck into the auto shop. They said faulty alternator, so 800$ later got a new AC Delco alternator on, next day, issue fired back up into full effect. Contacted Auto Shop, they re-diagnosed it for over a week. Found a faulty ground cable from the alternator to god knows what, 120$ fix, 40 minute test drive by auto shop, no issues. I had it home for 4 days now, took it out for lunch to meet a co-worker, issue fired back up the second I pulled into the driveway. This truly seems to happen when I am slowing down, applying the brake and coming to a stop. Sitting in park, or driving, zero lights going haywire. Its so intermittent that the auto shop couldnt get it to do it after the cable swap.

More research seems to point to spark plug wires, spark plugs, battery cables (Both Pos & Neg), ABS Sensors, or the last and most that seems to be the possible culprit is the brake light switch mounted to the brake pedal assembly. Few folks found this to resolve the issue I have but non mention the voltage drop. I have added two videos to show what I mean.

https://youtu.be/j8jABs3loCY

https://youtu.be/YMK-LF4VtoY

I am going to revert my truck back to standard headlight bulbs, fogs, and put the factory 3rd brake light back on just to eliminate the aftermarket lights from the equation.