Left tail light won't come on

[m3f_Bobby M3]

For about 2 months my little red screen has been saying "brake light circuit" and all the lights were fine and just a couple days ago, it now says "tail light failure".



I bought a brake light switch for the first message (haven't installed it yet).



But the problem with the left taillight is, it only goes out when I turn my headlights on. When i pump the brakes, all the bulbs work perfectly. Same for when the headlights are off, they go on when brake is applied.



I'm afraid that replacing the brake light switch won't fix this problem but only the message.



I'ma noob

[m3f_JPoland]

Replacing the switch doesn't necessarily mean the message will go away.

What I mean is, if the brake light is actually out then the message will still be there when the switch is replaced. That is the point of the whole thing, to tell you when a brake light is out.

Definitely install the new switch and if you're still getting the message then the problem is somewhere else.

[m3f_Aavi]

You can also remove the affected tail-light and check the connection points behind it. Sedan or Coupe?

[m3f_Bobby M3]

It's a sedan. So the brake light circuit message usually has nothing to do with 1 taillight being out? Or is it one of those trial and error things?

[m3f_Aavi]

search "tail light failure" using the search button...if that does not help and your problem is not solved I have a brand new left rear tail light for a sedan for sale.

[m3f_cbksupreme]

Bobby M3, don't be foolish and just buy a taillight to solve your problem. I had a similar issue here before and I figured it out on my own not to long ago: http://m3forum.net/m3forum/showthread.php?t=342799.



Here are a few troubleshooting steps you can try out



1. Check the fusebox and make sure the fuse is good.



2. Remove your left taillight.

a. Replace the bulbs that you notice are bad with the similar bulb from the right taillight.

b. Inspect your bulb sockets for corrosion. Simplly remove the bulb and see if there is any build up in there. If you're not familiar with electrical corrosion, it's a white powdery substance. Google it and see for yourself.



3. In order to insure that your left taillight is all around functional, remove it from it's housing. Then remove the righttaillight and connect you're left tailight into the plug. Turn on the lights and see if they're on. If they are, then you know you don't need a new taillight.



4. Remove your headlight switch in your dashboard. It's got two easily removable screws and two connectors attached to it which you just pull off. Once removed, shake it around a bit. If you hear any rattle inside chances are you're switch is broken causing no contact in certain points for the lights not to light up.

Note: If you removed the headlight switch, it maybe a pain in the ass putting it back in. With a little play moving it around and pushing it in evantually you'll get it in. The proper way to put it in is by using a long screw driver that you'll insert into the vent in order to push back air duct (or whatever you call it) against the corner inside there.



Alright that's all I got for now. I'm pretty buzzed in celebration of reaching the weekend once again after a long work week. PM me if you have any more questions.



Good luck!

[m3f_roarE36M3]

i gotta do some tail light maintenance myself. ever since it got real cold i've been getting a brake light failure on my OBC first thing in the morning. once the car is warmed up and i restart it, the light goes out. that and my horn stopped working. not a good start for the winter.