dome light doesnt work when opening from driver side door.
 

1995 E420

I have noticed that my dome light doesnt work when i open from driver side door. I have check the door switch it doesnt get any current or voltage reading on multimeter. But light works when i use passenger side door. I have also check all fuses.

any suggestions on how to fix this?

Regards
-Kamal

For the 300e models, we are advised to first check out the seatbelt warning relay, which is located behind the instrument cluster in the dash. (There are threads discussing this.) I don't know if anything changed in the 320/420 model updates. Good luck.

My humble "guess" is that you should pull the door switch, test for continuity through the switch, and pray it's the switch (which is easy to replace versus looking for a bad wire connector.)

I checked the door switch by swaping with right front door. switch works but the left front door does not read any current.

Same problem, though I do have current at the switch.
Just got my seatbelt relay in the mail.
I'll let you know how it goes.

Replacement procedure here:

http://diesel.web1000.com/5/

Website is temperamental, hopefully it works for you :)

If you click on it and get some weird search page, try copying and pasting the URL.

I recenlty install seat belt warning relay. Easy task after getting the input from forum. it took me about 45 mins. later editions have enough slack in the speedometer cable so i didnt had to disconnect any of cable in back of instrument panel.

thanks

Did you replace it or fix the old one.

On mine, I found some of the "metal" on the circuit board burnt out. Soldering a jumper wire fixed mine.

As a matter of fact, I've now changed my buzzer to a chime.

I replaced it with new one. I crack open the old one to see what was wrong. I saw the same thing as your, burnt PCB curcuit.

So then it is easily fixable.

Did you actually get the whole relay out of your car? It seemed impossible to me, so I simply used 2 butter knives to get the pcb board out of the old relay box then I slid the new one in.

I took out complete bracket that hold two relays. Once the bracket is out. thereafter it is piece of cake. i had hard time unpluging the socket out of relay. But i had to wrestle with it. In this process i droped on the nut behind the dash. I didn't bother to put that back. Now only one support hold the relay.

Yea, the plug takes a bit of work to take off and put in. But how did you get the bracket out? There is no room to work.

need a long extension and 10mm socket to open the nut in back. other one i used 8mm small wrench.

Kamal & wjm,
I'd appreciate a little help since I have been unable to access Speedy's website with his photos. I thought pulling the cluster would be the hard part, but with the MB tool it was really easy. Now, I see all these relays on the right side. I see (1) one goldish "nut" next to the speedo cable, screwed into the body & holding a piece of metal which holds a black plastic "thing" with two sets of connectors--is this the 8mm requiring the small wrench?? and (2) a bolt into the back on the firewall holding I don't know what- is this what needs the 10mm & extension??. Is there anything else to remove?? The relays to the far right are not involved?? (PS-what are they?) A brief explanation how to get to the villanous relay would be much appreciated--I really hate getting into a dark car at nite. Thanks so much.
Rich

Rich,

What model/year you have?

I never took out the entire relay. I simply undid one hex screw with a small rachet head on a hand driver. Then using 2 butter knives (or flathead screwdrivers), I squeezed open the relay cover (top and bottom) and removed the inner circuitry.

First remove screw on left side, and unplug. Once you get the butterknives into the top and bottom of the relay, grab the inners with some needle-nose pliers. Note how it came out. Then put and snap the new one in.

Here is a picture of screw removed.

Unplug the relay

Sorry, wjm. Its an 87 300e.
The hex nut is the one next to the speedo cable, right?
How did you get a rachet head to fit over it? With that out I'll remove the plug on the bottom of the relay & go to work w/the knives, is that correct? Or attack the firewall as Kamal did if necessary? Yes?

Use butter knives to remove the circuitry

Here is everything reinstalled.

In this picture you'll see what it looks like in my new installation. I replaced the buzzer with a Sonalert Chime.

wjm, I think on the 94 MB moved the hexnut a little to help out. Mine has less top clearance & I probably need the wrench. So the relay sits below that black thing & is reached by tilting up after unscrewing. The pics, worth a 1,000 words, as they say. Thanks again.

Rich,

I don't have a speedo cable in my 94, so I cant tell you. I think my picture should help with the screw I'm talking about.

The rachet head does not fit over it 100%... but certaily enough to get it off.

Once removed, the 2 relays will move enough to help with removal. Should have more than enough room to get the butter knives in.

Again, I've never taken out the entire relay.

As you said, your model year is a bit different, but with the right tool, you should be able to get that screw out.

10 mm hex nut cannot be seen due to presence of padding. two relay brakets are held by the two nuts one is 8mm and second one not visible is 10mm. 8mm is nut is easy to remove. but 10mm nut is removed by using extention and feeling the nut. There is not way you can see that because itz way back. 6" or longer extension will do the job. once you have bracket out then it is easy task. remove the relays using small 8mm nut(this 8mm nut is that hold relays in bracket) and replace with new one. While I was changing the relay, I droppped 10mm nut in back. I didn't bother to put that back. I only used the 8mm nut to hold the relay braket in place. I have pic at home that i will post that later.

It's Done!!
 

I did it this morning. Not too difficult, thanks to Willy's pictures. On the 87 300e the 8mm hexnut is a little lower & was easily removed with a hand driver, & I decided to avoid the butter knives & go for the firewall 10mm. I replaced the relay since it was only another 8mm, which was accessible. Dropped the 10mm once, but was lucky enough to get it out, then I packed paper towel into the ratchet socket & topped with 2-sided scotch tape to hold the screw while I inserted the extension. Worked like a charm, & now I have light. Thanks again Willy & Kamal.
Regards
Rich

Great news!

In my 94, it just not seem to be as easy as yours.

Oh, now that you have the old one out, take it apart. I bet you can see where the PCB board is damage/burnt out. I fixed mine by simply soldering a jumper wire.

If fixed, you can then experiment and change the nasty buzzer with a chime.

Willy

Willy, I planned to do that but didnt have time today. I shook the relay & it sounded like something broke off inside. I'll report back.
Rich