New Mercedes Owner Needs Help Please - PeachParts Mercedes-Benz Forum

ladams4 · #1 12-19-2007, 10:28 PM

Hello everyone I just bought a 1980 300D Mercedes it runs awesome but I have a few Questions about how to fix some of the stuff.

1. Radio does not work even tho there is power to it.
2. No Dash Lights at all.
3. Odometer/Speedometer does not work and the clock I really don't care about the clock.

4. The biggest of them all is that they sealed the sunroof shut I am guessing because of leaks But I would like to get it fixed. How would I go about doing that?

5. it does have some minor rust but I can fix that as I go.

Any help you could give I would really appreciate it. My Kids would too as they have to listen to me sing in the car! Payback is what I call it.

okc329 · #2 12-19-2007, 10:51 PM

to seal the sunroof? If the material is pliable, you might be able to get a grip on a strip of it and pull it out, one side at a time. I would not try to open the roof all the way at first. If there is a crank for it (mine has a removable crank for emergencies) turn gently after leaving car set in sun. As soon as you can see any of the exposed rails, squirt in a small amount of WD40 and close/open partially. As roof opens more, add WD40 to newly exposed rail surface working back and forth until you have it open. Once its open. inspect seals and repair/replace as required. If roof is electrically operated, fuse may be blown from an attempt to open it while sealed up.

Your best bet on radio is to remove and take/send to a shop familiar with brand/model of radio. Buying a rebuilt unit might be least expensive route.

Speedometer should be looked at by a shop which specializes in speedo repair. Look in yellow pages.

Dash lights could be blown fuse.

Clocks get gunked up and again replacement may be preferable to repair. Does clock light up at night? If not, may be associated with dash light problem.

Does anybody know if roof, if electric, shares fuse with any of the failing items?

280EZRider · #3 12-19-2007, 10:55 PM

On most of these W123 cars, dash light problems are from a blown fuse or the rheostat. Most of the time you can simply turn the rheostat knob back and forth rather earnestly and the contacts & spring will clean themselves. Since the clock is kaput, I would start w/the fuse.

The sun roof would have to be unsealed and opened before determing what to do next.

The 1st thing I would check on the speedo problem is the cable. It's most likely broken.

Welcome to the forum.

Larry Delor · #4 12-19-2007, 11:05 PM

The sunroof has 4 drain pipes. Two in front, two in back.
One or more of the pipes could be leaking at the joint where the pipe meets the roof. OR it could just be time for a new seal.

If you search, you will find lots of info - including clock repair...I believe there is a resistor (available at RadioShk) that fixes many broken clocks.

Get a new radio, and 3" speakers - the speakers you have in there now, are beyond cheesy - I'm surprised MB had the guts to put them in in the first place. The original radio will only have a L and a R out. Those leads run to the fader switch (behind the gear selector) and from there, go to the (cheesy) paper speakers. Either bypass the fader and re-wire it properly, or use the fader and original wiring - be sure and adjust the fader control on the new radio.

Have fun!

ladams4 · #5 12-20-2007, 09:41 AM

Sorry Im new to Mercedes What is a rheostat???

For the Sun roof the rails I am assuming thats what it is is rusted and the Headliner is coming down there.

The radio is an After market radio I think I may have found the problem The Antenna motor located in the trunk is not even where it is suppose to be It is lying in the trunk so that may be a ground right?

Sorry if I am Sounding a little stupid but this is my first Mercedes and Im a girl doing the work myself.

Thanks for all the help.
Lind

donbryce · #6 12-20-2007, 09:56 AM

I'm not familiar with your yr/model specifically, but the 'rheostat' is the dash lights dimmer, should be a small black knob to the left of the speedometer. You'll probably need to remove the instrument cluster to proceed further on trouble-shooting the speedometer and dimmer. Do a search here, lots of how-to info already available.
For the antenna, try connecting the cable coax lead from the radio and attach the braided cable to body metal (ground). You should be able to verify that the radio is picking up a signal, even if the mast isn't up. If you hear sound, go to the audio forum here and do some reading on how to connect/mount the antenna (which I assume is power).

ladams4 · #7 01-03-2008, 11:20 PM

Ok now I feel really stupid here now. The radio had a bad wire and was replaced and then I finally figured out what that lovely little button is that says Antenna It was off no wonder I couldn't get any radio stations. ok now i am having a problem with it starting when it is cold. *Shrug* I will keep searching thank you for all of your help. and still no dash lights or speed odometer I am using my GPS to tell me how fast I am going. I will figure it all out.

Larry Delor · #8 01-04-2008, 10:08 PM

Make sure your glow plug light is coming on. Once it is off, turn off the key, and make the glow plugs start over - then, count to 15, and try starting it.
Dash lights is most likely the dimmer switch - pushing, resets the trip odo...turning it, is supposed to brighten or dim the dash lights. The odo is another common item, that is not too hard to fix. Do a search for odometer repair in the Diesel section...there ought to be a link to a page that has hints and pictures. If not, you can probably figure out the trouble by looking at odometer contraption, and fix it with a spot of superglue.

ladams4 · #9 01-05-2008, 08:42 AM

The glow plug light come on when I turn the key on and then it goes off but will not start so i kept reading through all of the post here and went and had the battery tested and it tested bad. so I have to start with a new battery but the glow plug light blinks sometimes when I am driving. So I am assuming I need new glow plugs. I will keep searching on the other items as well. Thank you guys for all of your help here.

david s poole · #10 01-05-2008, 10:22 AM

you are correct,a blinking glow plug light indicates more than one bad glow plug.i would replace them all.even with a worn engine that glow system is so good that a start can be easily achieved at 25f.

ladams4 · #11 01-06-2008, 09:03 AM

The glow plugs will be replaced today I had to order them. Now if I can figure out the Gas gauge no matter if the tank is full or not it only reads 1/4 of a tank. so I will search on that now.
Thank you guys I really appreciate all of your help with this. I really love driving this car it is Awesome.

rocky raccoon · #12 01-06-2008, 10:13 AM

I no longer have a 123-body benz but as I recall, there is a manual crank access for failure-mode operation of the sunroof. I believe it was located in the truks under a side panel. I think it takes a wrench to operate. Sorry I can't be more specific but it was a long time ago.