I've searched and even posted in other threads but the issues I'm having have changed and gotten worse so I'm starting a new thread so it's all in one place and hopefully useful for someone else in the future.

Ok, so I got my second 8 back in February after an accident and have been having electrical problems.

It started with the keyless entry system intermittently working, sometimes the doors would unlock sometimes they wouldn't with either the key fob or switch. They would try to unlock and just seemed to not have enough power to open or like they were binding on something.

I also noticed the light on the dash that tells you when your headlights are on would come on when hitting the brakes, which I thought was weird. I later noticed that the drivers side parking light was coming on but was dimly lit when hitting the brakes.

Last week I had a problems with the room fuse blowing soon after I replaced it. What would happen is the interior lights would flash as if the doors were being opened, the light on the dash showing the doors are open would flash and I could hear a relay clicking, which sounded like it was coming from the keyless entry control module. A few days ago I removed the keyless entry control module cleaned all the connections with contact cleaner and also removed the ground in the passenger side footwell and cleaned and sanded the contact points and tightened it back down, the room fuse hasn't blown yet but the issue with the door locks is still the same.

Yesterday I swapped the Keyless Entry Control Module with one from a friends and the same problem still occurs in my car with the door locks, so we can rule that out. Next thing is to check the actuators, any advice on how to test them would be great.

My car has an aftermarket head unit which was installed by the previous owner, so today I decided to take everything apart and verify everything was installed and wired correctly. Everything seems to be right and anything that was tapped into appears to be correct, the only thing I found was with the black wire on the Pac Swi-Jack, it was connected to the red/black wire at pin 10 on the OEM Stereo Harness and connected to a ground. It should have only been connected to a ground so I corrected that issue. Another thing is every Ground that's Audio related(Metra Kit, Headunit, Pac Swi-Jack) is connected to the same ground wire and ran to the trunk of the car, I'm not sure why they did this or if this could cause a problem please let me know. I have to atleast pull apart the trunk and find the ground and verify there's a proper ground.

Today I now noticed that instead of just the one drivers side parking light that came on before both Parking Lights and Side Markers come on, the gauges also change to red as if the headlights were on when I press the brake pedal.

And to top all this off my Traction Control and ABS Light have recently started to come on and stay on steady after driving for a few minutes?

Any tips or advice you guys can offer would be great.

Thanks Kyle

 

Also forgot to mention I had my Check Engine Light scanned today and this code appeared:
U0167 - Communication Error to Keyless Control Module

 

Haven't had any time to look into this further, hopefully I will this weekend. If you guys have any ideas or tips as to what I should look for it would really be appreciated.

Thanks

 

Alright so I have some more info to add but still haven't found the problem.

This weekend a friend of mine also pointed out to me that whenever my headlights are on my brake lights are always on, not just the tail lights the Brake Lights, so I've essentially been driving at night with no brake lights....Definitely NOT Good!

I checked to see if the brake switch was the source of the problem by disconnecting it and seeing if the problem still occurs by turning on the headlights and seeing if the brake lights still come on with the switch disconnected, which it does so that's not it.

I also checked to see if it was a problems with the switch that controls the head lights by disconnecting that and hitting the brakes to see if the parking lights and side markers come on, which they do so that's not it either.

I spent a few hours looking at the Wiring Diagrams and the two systems don't seem to be integrated in anyway, the head lights and tail lights are but the brake lights are essentially separate?

One thing I do need to check is the ground in the trunk, I'm pretty sure the previous owner ran the ground for the head unit, metra kit, and PAC-SWI Jack to the trunk, Wondering if that somehow could be causing the problem, grounding issues always seem to cause the weirdest electrical problems.

Still if you guys have any ideas I could really use them at this point.

 

If I had to make a guess I would say that you have a serious amount of power going straight to ground. By chance...did the guy you bought the car from have an amp installed that you do not? Have you tried driving the car without the head unit attached? What other electrical modifications did the previous owner make?

 

Thanks for your help, another thing I did based off your comment of power going to ground I disconnected the amp power wire from the battery and the problem still occurs.

The search still continues lol

 

Ok with the Headunit, Amp, and Subs completely disconnected the problem still occurs?

 

So I figured out what the problem was, it's so stupid that's it's something I would have never expected to cause such electrical havoc in my car lol. So let's recap my parking lights and sidemarkers would go on when I hit the brakes, the brake lights were always on when I had my headlights on, and after driving for a little while my TCS and ABS lights would come on disabling that system. Guess what it was.....




























ONE OF THE DAMN LED TAIL LIGHT BULBS WAS SHORTING OUT, WTF!!!!

Glad it was such a small problem but man what a pain in the ***!
So lesson learned, start with the simple **** first when having electrical problems!!!!!!

Now on to fixing the problem with the drivers side door lock. I'm pretty sure it's just the actuator, maybe I'll check that out tomorrow.

 

Wow... I'm sure that's not something any of us would've guessed.

Electrical shorts are probably the very most difficult problems to troubleshoot on a car.