While replacing the front right door panel on my '91 350 SD, I shorted the power leads to the light on the door bottom. I thought this would simply blow a fuse. Now, the interior lights don't come on when the driver's door is opened and the warning buzzer no longer sounds if the key is in the ignition. The interior lights do come on if the front passenger door is opened (including the driver's door light). I haven't found any blown fuses under the hood. I'm stumped. Are there any other fuses or relays I might investigate? Did I burn up a wiring harness somewhere? Any other suggestions?

Greg

Take apart the seatbelt buzzer relay and you will find one of the traces inside is blown up. My car had the same problem when I got it. It was easily fixed by soldering in a wire in place of the burnt up trace. The buzzer relay is mounted up in the dash by the steering column, on the same bracket as the cruise control unit.

-Jason

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Thanks, I'll give your suggestion a try and report back.

Jason,
I removed the seatbelt buzzer relay (004 545 07 32), opened it and found a burned circuit board trace as you described. I soldered a jumper and installed the relay. Courtesy lights, seatbelt indicator and buzzer seem to be operating normally again. Thanks for your input!

Greg

I just did the same thing! Shorted out the wires and now have the exact symtoms described in the original post! Do I take the instrument cluster out to get to the relay or just go up from under the dash to get to it? Dumb....

__________________


1989 300E

2005 Acura TL

2011 Hyundai Elantra Limited

Swing hard! Take chances!

OK, just found the answer!

You have to pull the cluster to get to it. Two relays behind the cluster...it's the one on the left side.........

__________________


1989 300E

2005 Acura TL

2011 Hyundai Elantra Limited

Swing hard! Take chances!

Connecting both front door switches together will get the dome and entry lights working, but it won't make the headlight buzzer work.

If you take off the lower access panel and look up you will see the buzz box. Getting a wrench on the bolt holding the bracket in is a PITA, but it's not too bad.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Ooops! I omitted the car info.
It is a 1990 300 SEL.

Thank you so very much, everyone is really helping me and I need it!

I note that even though the driver's door courtesy light and the dome light don't work when that driver's door is opened, if I open the driver's door with the headlights on I DO hear the buzzer - I thought from this thread that that would not be working either - what's going on here?

I got the instrument cluster out with no problem at all and thought yipee this is a piece of cake. Then I couldn't see any relays and I knew I was in trouble.

I saw 3 plastic clips on the bottom edge of the lower panel but that isn't enough to get it off - where else are clips or screws to get that panel off?

Then, from one of you nice posters I'm getting the idea that I will need to take the bracket off to get to the relay, while I was thinking once I saw it it would just unplug and I could work on it. Why is this always so hard......

Would you please be so kind as to look at the thread for a minute to see my new post - I have a couple of pictures there. Thank you.

I have the instrument cluster out (easy but hasn't helped me locate the offending relay) and I have the lower dash panel out and still can't find the relay.
I have 3 pictures - one is the left side of the instrument cluster opening and the other 2 are looking up under the dash, taken from the driver's floor a couple of inches roughly in front of the brake pedal. I circled in blue the only removable relay I can find - it is not silver and there are no breaks in the circuit board.
Can you please give me a further help on where to look based on these pictures?
Thank you very much again.

Attached Thumbnails

     

The one NOT circled in the last picture is the buzzer. What you have circled is the coding piece for the cruise control comput... err, amplifier. The bigger box it's plugged into is the cruise compute... err, amplifier.

-Jason

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Thank you so much - maybe I'm getting close now.
So the one I want is above and to the right of the one circled?

It has a bundle of wires going to it - so how do I get it off to bring in the house and fix the circuit board - I sure don't intend to disconnect all those wires!!

Ohh, my back is killing me.

Just figured out that the circuit board is probably in the box with the female holes, not in the male plug with the pins, right? That solves the problem of not taking apart that bundle of wires.

1. The one I'm after is the squarish one above and to the right of the relay I circled, and NOT the rectangular one below and in line with the small one I circled?
2. I see a nut at the end of a bracket holding those three relays - that is the PITA that compu_85 was referring to and if I take that one nut off the whole bracket with all 3 relays will drop down loose?
3. If I take off that nut, will it go right back on when I'm done without crapping up the cruise control alignment?

The connector on the buzzer, like all the other control units in the car, simply pulls off. Yes that nut is the PITA one I'm talking about. Yes, the whole bracket will go right back where it was when you're done.

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

compu_85, you're a genius for figuring out how to make the repair in the first place.

I can't thank you enough for staying with me on this.

Good: I got it out, saw the burned trace and fixed it.
Bad: In the process, I bent the circuit board and broke 3 other traces. In the process of fixing them, I broke my loupe and burned my hand with the soldering iron.
Good: But it's fixed!
Good: It works!

A million thanks for all the help.
Now, if I don't break anything putting the bracket, ductwork, and panel back, and if I can remember how I took it apart, it will turn into a good day after all.

Again, many, many thanks for the help.
Don

When I connected the door switches together the headlight buzzer worked. You had a lot of patience to repair the relay itself. Too much time and trouble for me.

__________________


1989 300E

2005 Acura TL

2011 Hyundai Elantra Limited

Swing hard! Take chances!