[SOLVED] With a little help from my friends

I recently had some sporadic electrical gremlins that have me concerned. About a week ago I noticed that when I selected a left turn, both green arrows in the cluster would light up, much like when hazards are turned on. I chuckled and finished my trip about 3 min later. When I parked, I restarted the car and the issue was gone. I assumed because the car had been parked for the last 6 months it was just quirks from storage.

Drove the car for a week with no issue.

Yesterday, I drove home from work (20 min) and immediately noticed the same signal light issue. This time the selected direction arrow would be normal brightness and the opposite would be slightly dimmer. When I got home, I left the car running and checked the exterior lights. I noticed when the left signal was selected it would flash, and alternately the right signal, side marker and the 194 bulb in the high beam reflector would flash. It seemed I might have a bad ground. But wait, it gets better! I shut the car off, when I went to restart, the dash would light up, radio, HVAC blowing...no starter, sad panda face! I dont recall hearing a solenoid contact in the engine bay distribution box (remembering that part is fuzzy). No codes on AP. I swapped the relay with the rear defrost relay, still no go, but relay was engaging. Thinking the BCM might be at fault, I disconnected the battery ground for a few minutes hoping to reset it, still no go. Turned the headlamps and fogs on and heard what sounded like a smurf sized machine gun blast...not a long one, more like a "son-of-a-bitch" release. Im assuming what I heard was a good number of the relays in the engine bay distribution box activating. Car started like a champ. Cycled between off and starting the car about 5-6 times without any complaints. Everything seemed normal again.

So far, thats where Im at. My car is down for a few days while I sort out a replacement left front CV shaft (probably from the dealer $$). In this time I plan to start from the beginning and hit every mark I can to clarify it isnt a simple problem with a simple solution.
1. Clean and inspect battery terminals. This was done 3 weeks ago, however I will repeat as Ill be removing the battery anyways. Im going to follow the big cables all the way to the starter, distribution box terminal and the ground points to verify good. Clean up the ground points and DE grease them.
2. I would like to unplug the BCM connectors and inspect them, reconnect them and also ensure the unit is secure. I have removed the kick panel and looked at the BCM. No visual issues like water or wire abrasion, lots of taps for the dealer installed security system options. I will grab picture.
3. Open the distribution box in the engine bay and clean up the BATT terminals, check and test all the relays, verify all fuses are good. Possibly open the backside and check for burns, damaged wires etc.
Here are the questions...
Does the BCM activate selected features by completing ground signals to the relays? Could that be why seemingly unrelated circuits were affected because they are controlled through 1 component. This just helps me verify assumptions and understand the system.

With the battery disconnected I shouldnt have any issues requiring reteaching if I disconnect the BCM plugs? CanBUS is not my strong suit, its still a bit voodoo to me. I dont think so, just checking.

If I were to remove all the relays and fuses, would a soaking with contacts cleaner be of value or could I cause more issues?

This car is garage kept, not driven in the winter or on dirt roads and has never had any rust proofing therefore it is pretty clean. Fortunately that rules out any of the negative issues related.

I will only be able to report success rate after I experience the next episode, whether better or worse I will report back periodically.

 

I have seen so many weird electrical issues forming and harness issues are popping up now. I myself has this. So I'm thinking KISS. KEEP IT SIMPLE, STUD. Or stupid.

So I would go set a fresh ground. A ground wire can be had cheap and can defeat a bad ground issues. Find a solid ground on frame and on the car.

 

Got a few moments in today. Started at the battery terminals and worked my way to the starter connection and the ground on the bracket by the starter plus I followed to the positive posts in the Distribution box. Cleaning as I went, all looked good. None of the connections looked compromised.

Ive pulled the starter and Im going to take it to my Alt & Starter guy to bench test it for me. All looked good on a visual.

My wires look good, no green, the copper is still copper coloured. Im not finding anything corroded, burnt or worn. The ground strap from the engine to the frame on the passenger side looks good too. I will pull that and clean it. I havent reassembled anything yet. Im also still unsure about unplugging the BCM as of yet. I didnt see anything at the BCM as far as damage or concern, and although I despise wire taps they are for the anti-theft system which hasnet been affected.

 

their is a whit connector bolted to the body of the car behind the driver head light in front of the main fuse box. Unbolt it, remove the plastic connector cover and clean all the little metal spades on it. that's ur ground for ur head lights and blinkers.

here is a pic of it

 

Haha, I just took a pic of that and was going to look at the schematics and ask. Thank you, I will try that.

Took the starter to get tested. All is good, doing what it is suppose to.

 

I havent done much else on this subject and I also couldnt do much testing as the car was up on stands with the left front CV shaft out for rebuild. I cleaned up the ground unit @rrodriguez9921 mentioned. Yesterday I was able to pull the car out finally and went for a drive. I experienced no issues, as well as this AM when I pulled the car out of the garage to wash it up. Time will tell, I figure if the issue dosent reappear in a month I will call it safe. I do think the most likely candidate was an issue with the grouping of grounds.

 

Update: 0 issues since. Problem solved!