Help-

In the space of 1 day, my tail lights failed. Went to my daughters basketball game and another parent points out that my tail lights are out.

Back up lights, turn signals in rear, brake lights in rear and license plate lights work. Looked up fuses- no fuses nor relays listed for tail lights-called Bill Ball- told tail lights on parking light fuse. Replaced defective fuses 40 and 41, surprised that both fuses out, expecting tail lights to come on- no luck.

Am getting all 6 bulbs from DEVEK and hoping replacing them will do it-
any wisdom greatly appreciated !!

Mike

See final post for solution and recommendation

Mike

 

odd they would all burn out together unless they got a surge. I am always replacing bulbs. Quite common. I get the bulb warning light after I wash my car. It is a sensitive system. Be sure to post your findings.

 

Have you checked the lamp control module at the side of the passenger underdash tray?

 

Heinrich...ah, so, that does more than monitor the bulbs?

Michael, what you have not working are refered to as "clearance lamps" in the wiring diagrams. Also, fuses 40 and 41 are labeled "side marker light" fuses (one right and one left) in the WSM. So, I would think the side markers should have been out as well. Something odd going on here.

As a test, we can swap my bulb control unit into your car as they are the same 87-95. They are quite expensive.

 

Bill twice now i've seen that module take out lights. on one of my cars it killed the right middle tail and sidemarker. I do believe it acts like a light relay.

 

Thanks, Heinrich. We'll test it.

 

Good call Heinrich ! that control module does in fact control the lights and one failure mode is to cut the power to the rear lights/ stop lights depending on what burns up inside the controller. It also does the bulb check function to turn on the central warning lights ....not so much a relay but part of the wiring with lots of interesting little electronic bits on a circuit board inside the controller.

 

Why thank you Brother

 

Jim:

I saw a confusingly written (translated) note in the WSM that shows an emergency bypass plug. So, it makes sense now. Thanks.

Mike, if you want to do the swap before you order this part (over $200 new), come by over the holidays. We can jump the controller until you get the new part.

Thanks to Heinrich and Jim!

 

Thanks Bill-

will call later tonite to setup .

Mike

 

Use the schematics and just permanently jump the side marker/tail light circuits at the LCU/Warn.
Personally, I would rather have the fault isolate itself -a burned out bulb for instance- than try to figure out which of several bulbs has failed muster and left me driving down the, road at night,
with a glaring red warn dialog/flashing red warn -why don't those friggen lights ever burn out?-.
That gets very old, very fast. and is not longer, if ever, needed. High tech and spiffy 20 years ago that damn LCU integrated with the dash/central warn is just a major bother today. Someone posted a Benz or VW jumper with PN a while ago ... should be in the the archives.
Grumble, grumble...

 

And a couple more little bits of trivia..........

That control module disables the cruise control if it sees a brake-light failure.

Guess how long it took me to figure out why my cruise control had died!!

You can't replace the incandescent bulbs with the new, practically-infinite life LED units because the control module can't see that much-reduced current draw of the LED's, so it sets a failure indication (and kills the cruise control)

 

Porken made up a bypass plug...
https://rennlist.com/forums/showthre...t=bulb+control

The WSM indicates:

 

Bill,
Thanks for that re-post.
Brian,
Trivia my butt!
I didn't know that about the Cruise. Much Thanks.
Bet your Cruise is like new though.

 

Well, Mike came over and we swapped in my bulb control unit. No tail lights. Checked the fuses...BOTH 40 and 41 (R&L parking lights) were blown. They were 10 amp (supposed to be 5). Replaced the fuses correctly - blew immediately. Since this is with my working controller, I am not blaming the controller any more.

So, there is a short that is blowing BOTH parking light fuses as soon as the lights are turned on. Mike just had extensive paintwork on the car. I removed the tailight and looked closely at the wiring and saw nothing unusual. I have no experince or skill with tracking down shorts. Does the fact that BOTH sides blow help pinpoint the source? Is the paintwork a clue or just coincidence.