W126 Driver's Door Courtesy Light - PeachParts Mercedes-Benz Forum

gskurka · #1 08-10-2009, 02:22 PM

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

compu_85 · #2 08-10-2009, 02:36 PM

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

gskurka · #3 08-10-2009, 07:13 PM

Quote:

Originally Posted by compu_85

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

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

gskurka · #4 08-29-2009, 12:44 AM

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

big dog 2 · #5 12-20-2009, 09:10 PM

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....

big dog 2 · #6 12-20-2009, 09:35 PM

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.........

big dog 2 · #7 12-20-2009, 10:42 PM

Grrrrrrrrr.............on a W124 the relay is actually buried somewhere under the dash in the upper left hand corner impossible to reach. Guess if I want the overhead lights to operate off the driver's door, I will have to jump the passenger door switch power and ground to the driver's door switch bypassing the portion of the relay for the driver's door.........how do I get myself into these little headaches? Should work but what a pain..............

big dog 2 · #8 12-22-2009, 10:54 PM

Jumped the power and ground from the right door switch to include the left door switch. Everything works again...........

drosen · #9 06-17-2010, 05:19 PM

Hi to All:
Well, now I have the same problem. It was no problem at all to slide the instrument panel out, but I need HELP!!!

I just can't recognize where the relay is that I need to take out and solder. Can anyone PLEASE give me a little more description on where that relay is?
I would appreciate it sooo much.
Thank you.
Don

p.s. Worst case (I really don't want to do this) but if I need to jumper the two wires from the passenger side as on poster suggested, can he or anyone else please tell me the color codes or how to find which set of wires is coming from the passenger side and which set is going to the driver's side? I have the instrument panel out and I am assuming I can make the splice in there somewhere).

big dog 2 · #10 06-17-2010, 08:44 PM

I also could not figure out which relay or the wires so I........................

Simply jumped the wires from the good switch on the passenger door and pulled them across under the dash (out of sight) to the driver's door switch. Works fine now. Think it took an hour to two to do it.

gskurka · #11 06-17-2010, 10:09 PM

Don,
As Jason described in post number 2 above, "the buzzer relay is mounted up in the dash by the steering column, on the same bracket as the cruise control unit". I accessed the relay on my '91 350 SD by removing the panel under the steering column. There was no need to remove the instrument cluster. It also helps if you have an eye loupe or magnifier to inspect the traces on the circuit board once you get it open. Good Luck.
Greg

compu_85 · #12 06-17-2010, 10:22 PM

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

drosen · #13 06-17-2010, 11:08 PM

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......

drosen · #14 06-18-2010, 12:55 PM

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.

compu_85 · #15 06-18-2010, 01:47 PM

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