92' 735il Mustard Relay Replacement Issues (Tail-Light) - solved

[cnorto20]

Hey guys, new member here long-time browser of the forums. I'm really appreciative of all the helpful information I've received off here. Thanks for everyone's time and effort making these boards useful.

Issue: When I turn on my headlights at night, the Right Rear night-time running tail-light, doesn't illuminate.
It's not the bulb, I replaced it. It's not the socket, I replaced it. It's not the tail-light assembly itself as far as I can tell, because all the other lights work fine.

I read all the reports of the Mustard Relay failure being responsible for light issues like this. All the indicators fit my situation.

I bought the replacement Audi/VW version of the mustard relay that E32 users commonly replace with as a cheaper option than the BMW mustard relay. Here it is-part number 447959875 (electric window control by Hella) It's supposed to serve as a cheaper direct fit.



I noticed that the prongs on the VW version are different than the stock relay that is in the mustard relay's position currently:


Regardless, I gave the replacement relay a shot and nothing changed. Still the same tail-light being inoperative.
Here's the board in my 1992 BMW 735il-


And this is the empty spot that I put the new replacement relay in-


Is that even the right spot for the replacement relay?? There's so many different pictures and colors of relays online, it's hard to tell if I'm even using the right relay slot. In any case- the prongs connect and slide in easily enough- just that there's no change in the tail-lights condition, it stays unlit.

I'm out of options and at my wit's end here as to how to fix this light myself without having to take it to the shop. I know the Audi/VW replacement part maybe not perfect, so I also ordered the stock OEM BMW expensive part as well. More expensive, but it's in the mail on the way.

I really don't see why the VW relay wouldn't work though. I think I'm missing something here. Can anyone please give me some options here as to how I might fix this? Thanks so much for any help.

[CroughtonE32]

Looks like you have the right spot from the boss's fix page http://twrite.org/shogunnew/fixes/mustardrelay.html

[shogun]

That does not look like these are the prongs of a mustard relay. What is the exact month and year of production of your car? 1992 is not enough. Use your VIN and check in realoem then select here the correct wiring diagram,
http://shark.armchair.mb.ca/~dave/BMW/e32/
also read this thread http://www.7-forum.com/forum/5/musta...ay-221830.html
The info on my site for that is a bit confusing, it is also for the LKM-L and not only LKM-B. See the headline in the DIY article: Resolder and fix the infamous mustard relay (for LKM-L).There was always a confusion more than 10 years ago when that was changed. The technical info at that time we had was only available for 735 and 750, not for 740 and that document was from 1988. Apparently on the newer LKM this function is integrated into the LKM.

What exactly is mentioned on the relay you pulled there? p/n etc

Based on the 1992 ETM you pulled K19 X 51, which is the compressor control relay , that is the ETM for production 9/1991 - 8/1992.
Also in the 1993 ETM K19 is the compressor control relay.
1991 ETM shows in that position K7 X60 parking light monitor relay

So it looks like your car does not have a separate parking light monitor relay and the fuction is integrated into the LKM

[cnorto20]

That does not look like these are the prongs of a mustard relay. What is the exact month and year of production of your car? 1992 is not enough. Use your VIN and check in realoem

Well as it turns out I was completely wrong. I drive a 1991! Specifically 09/91

also read this thread http://www.7-forum.com/forum/5/musta...ay-221830.html

I will read this, thanks.

Not sure if I have the LKM-L or LKM-B....

What exactly is mentioned on the relay you pulled there? p/n etc

The stock relay I pulled reads- (Bosch 0332014456) (12v 30A) (1378238 167 P (or B?)1) (85 87 86 30) Each side of the relay, respectively.

[CroughtonE32]

I think you're dealing with one of the orange relays. Check this part number for Mustard or Daylight relay.
61311378052

[XAlt]

Yea, that car doesn't have a traditional mustard relay. I think you can just pull the LKM out of an E34 and go from there.

09/91 is MY1992. Coincidentally the same month as the ETM K19\51

[shogun]

9/1991 is 1992 model year, so based on 1992 ETM you pulled K19 X 51, which is the compressor control relay , see is the ETM for production 9/1991 - 8/1992. Try another LKM, yours should be a LKM-L, it is written on the LKM what you have, it is next to the CCM.
Did you check with a multimeter if there is power on the taillight?

[cnorto20]

I'll be checking with the multi today.

Thanks everyone for your help I'm hope by the end of the day I'll have this sorted.

[shogun]

LKM and CCM pinout http://www.bimmerboard.com/forums/posts/1175396/

[cnorto20]

Well I fixed the problem yesterday after some thinking and just starting back at the basics.
It was just a matter of sanding and cleaning the contacts and sockets. There was a lot of corrosion getting in the way of a closed circuit I guess. I checked them all with the meter, and I'm in good shape now. I'm so glad it wasn't a bigger issue.
After checking them all, I decided to just order replacement sockets and bulbs for the whole tail-light assembly. They were all in pretty bad shape, even though they were operating.
Thanks so much for the help everyone.