Taillight Failure?

[Phillips0417]

My OBC always throws a " 1 Taillight Failure" Signal whenever my lights are on. I get out and check it and indeed it's out; I try to jiggle it, take it out look it over and put it back in but nothing happens. It's still out. In some research I've found it says these cars are notorious for corrosion in these areas, but I haven't found any as of yet, but haven't had the taillight assembly out. Should I get a new plug, process of elimination? I'm not sure where to start. Thanks for any input.

[Manolito]

First suspect: The wiring harness where it flexes near the trunk lid hinge. There is a special type of wire with hair-fine copper strands and teflon coating that should be used for wiring harnesses that go through door hinges. BMW failed to use the proper wire in the section of the wiring harness that bends when you open the trunk lid. My wife is a school teacher who hauled stuff in her trunk every day, so the trunk was opened 4 times a day for 8 years. The wires failed where they bend under the trunk lid.

I cannot find flex wire for sale retail, though you could score some from the hatch of a station wagon or hatchback at a junk yard. I would look for a Volvo wagon because I know they use good wire in the rear hatch. Since my '97 trunk is rarely opened any more, I just used standard stranded wire from the auto parts store to replace the wire in the wiring harness near the trunk hinge.

On one of my e36s, I ended up removing the tail light assemblies, cutting off the plastic electrical plug receptacle with a dremel tool, soldering the pins to the metal traces, and epoxying the plug receptacle back on. While I was at it, I cleaned up around all the socket holes using steel wool.

Use matched, nickel-plated bulbs of the correct size in all sockets.

As I recall, there is one filament in one tail light bulb on the '97 328s that does not do anything. Its trace is not connected to power.

Getting the assembly loose from the car was the hard part. After 10 years, the seal around the assembly is stuck on pretty good. Remove the nuts. Remove all the bulb sockets so you don't break them, then stick pry bars in through the holes in the body where the sockets go through, and carefully pry off the assembly. I have read that others sprayed silicone spray around the seal to get it to let go of the body. That might help.

[Phillips0417]

Wow, thanks a lot, I'm gonna try that tomorrow in my garage, see if I can get it out and work on it a little bit. Yeah, I've heard it's tough gettin' them off of the body. A good cleaning can't hurt anyways right? Thanks!

[Tassie_328i]

Have you seen this thread

E36 "brake light failure" cause corrosion DIY FIX

This shows a brake light socket corrosion and i think its typical of what happens and how to fix it.

EDIT:

Have to second Manolito's comments on the boot Wires. I opened mine up and found the signal wire for the boot light had completly severed and two others had the insulation broken on them. Plus i opened up my sisters car when she bought it and two wires had completly severed and about 4 others, (nearly all off them) had some sort of insulation failure! Not sure how it hadn't blown any fuses or had more problems.

I urge any one who owns an e36 to go out and cut open that wiring loom! Based on what i've seen i bet you'll find some level of damage.

[Phillips0417]

Thanks a lot for your help, I'm gonna get in there and check it out, even if there's no damage, it sounds like it's still a good idea to change or protect the wiring better. You would think BMW would have corrected this problem. Thanks for the help, will return for results.

[Phillips0417]

Hey, I get my whole taillight assemblies out, not too hard to get off by the way, must've been off in the past, TOTALLY disassemble everything, separate it all, from the electrical to the ABS Taillight assembly. Look over everything, absolutely PERFECT, no corrosion whatsoever! I look over the whole electrical contact assembly, the pins, all that. Nothing, perfect. And very clean I might add. The lady I got the car from kept it in a garage, so that could explain why there's no corrosion. Anyways, I get everything back together, re-install them on the car, and as before driver side works perfectly, passenger side taillight still out. Hmm. I noted before which pins are for the taillights. So I get a jumper wire and jump it from the driver side pin to the passenger side pin, NOW IT WORKS!! But two lights are working on the passenger side now when only one is lit on the driver side. The outside light on the driver side is working, not the inside, I'm not sure if this is normal, or exactly how many are supposed to illuminate. I thought is was only one, the outside because as far as I know, there is no problems on the driver side. As said, now two lights work with a jumper from the driver side. Take it off and again, nothing. Which leads me to the car, I ran out of light to do too much more investigating, but the wires leading to the trunk seem to be okay. Everything wrapped and intact. Perfect. I have to get in there and check the wires more in depth. Sooo, anybody experienced this problem before? I thought it could be the light, so I jumped it, but it works, so that would lead one to believe it's some tiny electrical issue in the trunk, passenger side light right??? And anyone know which lights illuminate on a 325I for taillights? Just the one outside or outside and center? Thanks!

[Phillips0417]

Hello all, after doing more research, and I'll try not to write you guys a book here k? K..Well, I found in other threads on another site that the headlight switch itself could be bad meaning the contacts for the right side parking lights are out, I went to check it and low and behold the front light is out too. I'm gonna order a new headlight switch and will let you know results.

[Tassie_328i]

I assume you have you checked the fuses?? Because the left and right hand side park/tail lights are run off separate fuses. You need to check #37 (i think)

If its blown you'll be missing your lisence plate lights aswell.

And there are 4 (2 each side) tail lights.

[Phillips0417]

Yeah, of course I've checked the fuses, and I do have license plate lights. For some reason or another, mine has just one fuse pertaining to parking lights; and it is in location #37. I looked in the book and it says the same thing. So I only have one working taillight on the driver side rear, parking light front, but nothing on the right side of the car. Turn signals work, back up and brake, but no parking.

[Tassie_328i]

i thought you would have checked. The fuses are labelled a bit funny cause mine reads like its only one fuse but i took #37 out and the rhs went out, left hand side stayed on. Anyway its irrelevant. I'd say it must be in the switch then.

Check and make sure the harness in the back of the switch is seated correctly i guess as a start. Ideally you need to temporarly swap one from a donor car to see if it makes a difference.

[Phillips0417]

Sorry if I sounded rude, didn't mean to; I ordered a switch from bav auto and should be here by friday. Will return soon, have couple other questions I'm gonna thread here in a bit. Thanks!

[Tassie_328i]

Originally Posted by Phillips0417

Sorry if I sounded rude, didn't mean to; I ordered a switch from bav auto and should be here by friday. Will return soon, have couple other questions I'm gonna thread here in a bit. Thanks!

Not at all. Let us know how it goes

[Phillips0417]

Just to let everybody know, I just replaced the headlight switch and VOILA!! ALL lights work!! To anybody with this problem in the future, replace your headlight switch before trying to chase an electrical problem, relatively inexpensive and best place to start! Thanks everyone for their input!