Resurrection of a 90 420SEL issues - PeachParts Mercedes-Benz Forum

cphilip · #1 01-13-2020, 05:01 PM

The old gal has been locked up in a garage for almost 3 years with very infrequent starts. I am trying to bring her back to life. She starts well and runs Well. I haves a few known things I need to do once I get good battery life restored. But a few odd things haves cropped up that did not exist last times she was on the road. Things that seem to be a result of sitting.

For one, the lamps that blink in the overhead that indicate that the seat belts are not fastened blink all the time. Wether the seat belts are fastened or not. Even if you are not in the car at all. Even when the key is not turned on or even in the car.

Second thing, may be related or not, the locks do not respond. The one with the key in the door locks but the others do not respond. Think this one had vacuum system? So I can see that maybe I need to investigate that system. Something perhaps it not working right from sitting.

And the antenna no longer responds. That one I can live with for a while.

The priority is getting those seat belt warning lights to go off. Anyone got an idea where to start? I do not care if the system works as no longer need a nanny... I just want them to go off so I can not drain the battery. Or drive me crazy.

My Independent mechanic is no longer in business so I am on my own. This car is just about to turn over to 350,000 miles. And runs like a top by the way. Is extra nice condition too. Interior and exterior.

daantjie · #2 01-14-2020, 02:58 AM

Door vacuum is supplied by pump in the spare wheel well. They usually go bad after so many years. Kent Bergsma at ************** has a good video on YouTube on this topic.

nulu · #3 01-14-2020, 08:54 AM

Seat belt light sounds like warning module its behind instrument cluster. Relay looking box about11/2 by 3 inch, held by 8 mm bolt, unplug it light should go out

cphilip · #4 01-14-2020, 11:15 AM

Quote:

Originally Posted by nulu

Seat belt light sounds like warning module its behind instrument cluster. Relay looking box about11/2 by 3 inch, held by 8 mm bolt, unplug it light should go out

I can assume this is inside the vehicle... but can it be accessed by crawling under there? Or do I need to pull something to get at it?

cphilip · #5 01-14-2020, 11:21 AM

Quote:

Originally Posted by daantjie

Door vacuum is supplied by pump in the spare wheel well. They usually go bad after so many years. Kent Bergsma at ************** has a good video on YouTube on this topic.

LOL... I am sure that needed censoring... Darn it. Maybe you can post it in a code that I can figure out?

Diseasel300 · #6 01-14-2020, 02:56 PM

Quote:

Originally Posted by cphilip

I can assume this is inside the vehicle... but can it be accessed by crawling under there? Or do I need to pull something to get at it?

It is under the steering column. Drop the lower dash cover under the steering wheel and you'll see it. You can unplug it without removing it (removing it is a *$#^&%*)

Quote:

Originally Posted by cphilip

LOL... I am sure that needed censoring... Darn it. Maybe you can post it in a code that I can figure out?

M E R C E D E S S O U R C E

I'll also add my own experience here - I had the electronics fail in mine and stayed on all the time. Eventually it turned on the light as well, then failed to do anything at all. When it failed, it let the magic smoke out (you could smell it). Replaced with another dome light assembly and all is well.

cphilip · #7 01-14-2020, 08:02 PM

Ok.. I got some digging to do, Thanks Guys.. and or Gals if the case may be. Ill have to wait until this rain stops as the garage is too tight for me to work in. I gotta pull it out a bit to get the doors wide open.

Jorn · #8 01-16-2020, 02:12 PM

Like said before the relay box is a ***** to remove, mine wasn’t working and replaced it with one from the junk yard. Never took the old one out, just velcrowed the replacement on top of the old one. Saving myself a lot of aggravation.

cphilip · #9 01-21-2020, 11:11 AM

Good idea. Id be happy with it just disconnected. Now... since my first posting this thing has quit going off without the key on. So that helps buy me some time. We went from constant rain to sub zero temperatures. At least now I don't have additional battery drain. And the Battery tender can keep up and keep the battery full. Its only annoying while operating. At some point it will warm up here and I can get some time to get under there, find it and unplug it.

Someone wouldn't happen to have a picture of this little bug would they?