E36: Brake ground wore location

[radicalr6]

Very odd, my dome light, gauges, will flicker when I press the brake pedal. At times the radio will restart.

Does anyone have a diagram or can point me to where I can check the brake ground?

Thanks all


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[66 6]

Check your alternator output. Battery when off should be @12.5 with the car running 14ish. I know this does not check amps but it's an easy way to diagnosis the alt. I've seen your issues twice before when alts were failing.

[samy01]

i'd check the brake light bulbs

had something similar on another car once, some wrong bulbs were shoved in there making false connections and idk wth was going on in there

[Kapoosta]

+1 to checking alternator output. I was sitting in a drive thru and every time I took my foot off the gas pedal, the gauges and lights flickered and radio would cut out. It died as soon as I got out of the drive thru.

Does it happen with the car off and the key in ACC position?

[radicalr6]

i'd check the brake light bulbs

had something similar on another car once, some wrong bulbs were shoved in there making false connections and idk wth was going on in there

Pulled the brake light fuse!! And problem is gone! Gonna stop by autozone right now. Fingers crossed


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[Nanniepoo]

Check the trunk wires as well. There's a sticky I believe.

[radicalr6]

So changed out the brake lights and still same problem... Doesn't mater if I have one bulb in or both the problem is there. Doesn't matter which side bulb is in.




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[samy01]

and what if both bulbs are out ? maybe you have a short somewhere.

[radicalr6]

So changed out the brake lights and still same problem... Doesn't mater if I have one bulb in or both the problem is there. Doesn't matter which side bulb is in.




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Both bulbs out, all is fine....

How would I pin point the short?


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[Eric93se]

Like previously mentioned, you have to check the wiring in the trunk, pull all the trim off the left side and expose and follow all the wireing. Also check the wiring that goes up and along the left side of the trunk lid.

[samy01]

i dont think its the wiring. because if the bulbs are out and you press the brake pedal and it's all good then the short isn't somewhere in the wiring before the bulbs. if it were the case then he would still have problems without bulbs. are you really sure your bulbs are the correct ones? could you post here whats written on the bulbs? how do your brake lights look when someone presses the pedal? weak or normal?

[jmo69]

You could have a shorting or broken wire in the bundle by the trunk hinge.

[E36328Coupe]

Does the problem change if side marker lights are on? Check all combinations of lights to establish if a common earthing problem.

The dash lights come on with the side lights (or whatever you guys call them) so the path for the brake light circuit to affect the dash lights is through the side light circuit.

[mikeysentra]

Had a similar issue and the trunk lid harness was to blame. Soldered the wires back together with heat shrink and all is well again. Still thinking about spending the 50.00 bucks for the new trunk harness, for longevity.

[E36328Coupe]

Had a similar issue and the trunk lid harness was to blame. Soldered the wires back together with heat shrink and all is well again. Still thinking about spending the 50.00 bucks for the new trunk harness, for longevity.

If you replace the wires a couple of inches either side of the bend a new loom will last no longer than the repair.

[radicalr6]

i dont think its the wiring. because if the bulbs are out and you press the brake pedal and it's all good then the short isn't somewhere in the wiring before the bulbs. if it were the case then he would still have problems without bulbs. are you really sure your bulbs are the correct ones? could you post here whats written on the bulbs? how do your brake lights look when someone presses the pedal? weak or normal?

I also don't think it's the wiring. I check the trunk wiring and all is good there.

If I even have one brake light bulb inserted and I press the brakes the issue persists. As soon as I remove both issue stops.

Also just noticed that at night the dash warning lights such as the airbag and check engine will flicker when pressing the brakes.

Pretty sure I have correct bulbs. I will post the bulbs today.


Question though. If one of the tail lights has a potential issue/short. Would this reflect on the other one as well?


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[radicalr6]

Issue fixed: replaced left side tail light assembly with another one and issue went away.


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