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Discussion Starter #1
Hello,

New owner of a '91 350SD. I have previously owned a '79 240D, '87 300E, '88 560SL and '99 E430.

I'm not expecting great things of the 350; It is a transitional car. Maybe I'll get lucky and get more life from it than I expect.

I do, however, need to get the wipers and windows working. The wipers are stopped at the far end of their stroke. The PO tells me this happened once before. The shop "disassembled" the fuse box and the wipers commenced to work. The shop could not directly attribute their work to the restoration of functionality. Now that they are disfunctional again, I need to get them back. All four window switches are inoperable as well. I'm assuming the two are related, tho they may not be. Any suggestions where to start?

Thanks!
 

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Hello,

New owner of a '91 350SD. I have previously owned a '79 240D, '87 300E, '88 560SL and '99 E430.

I'm not expecting great things of the 350; It is a transitional car. Maybe I'll get lucky and get more life from it than I expect.

I do, however, need to get the wipers and windows working. The wipers are stopped at the far end of their stroke. The PO tells me this happened once before. The shop "disassembled" the fuse box and the wipers commenced to work. The shop could not directly attribute their work to the restoration of functionality. Now that they are disfunctional again, I need to get them back. All four window switches are inoperable as well. I'm assuming the two are related, tho they may not be. Any suggestions where to start?

Thanks![/QUOTE

All the window switches can not go bad at the same time and all the window motors can not go bad at the same time either

Open the fuse box and check the fuses that control the windows and renew those if needed also check the ground connections for the window switches.
I am almost sure ground connections are loose or rusted or disconnected. also check for the window wire short circuiting.

By the way your car is very rare car. Keep it if you can.

Sahai
 

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Fuses so often cause odd gremlins on these cars due to corrosion of the contacts. +1 just replace them all.

There is a wiper relay, not sure which one it is but i would suspect its that causing your wiper fault.
 

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I had an issue with my wipers not returning to the park position when I turned them off. The problem was with the relay for the wipers. I took it out of the fuse box and cleaned all the contacts as best I could with contact cleaner and emory cloth. It's been working perfect ever since.

I don't have a diagram of the fuse box and relays to point you to the right one, but the relay you are looking for is fairly large, ~ 1.25" x 2.5", and has about 8 or 10 pins sticking out the bottom of it. I'm sure someone on here much more knowledgeable than me will be able to point you to the correct relay.

Also, get a kit containing copper fuses of various amperages and change every fuse in the fuse box. Clean all the contacts in the fuse box before installation. This one step will cure about 90% of all electrical problems.

Adios,
Mike
 

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...I don't have a diagram of the fuse box and relays to point you to the right one, but the relay you are looking for is fairly large, ~ 1.25" x 2.5", and has about 8 or 10 pins sticking out the bottom of it...
These generic diagrams might be of some help:
 

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Discussion Starter #6
Thanks for the good information, I'll start with the fuses when I get the car home this weekend. If this uses the ceramic euro fuses, I have plenty on hand. I "assumed" the PO's shop had already done this, but I'll give it a thorough clenaing and replacement, and the same for the relay.

The car is actually quite nice. No rust, as the PO would frequently "oil undercoat" the car. The white exterior needs a wax, but that's all. The blue interior is also nice, no cracking of the dash. It has a new radiator, exhaust, transmission, shocks, tires, belts and a fancy stereo with all new speakers and amplifier. It also has all its receipts since new.

I had been looking for a 300SE, but they are not thick on the ground here, and I couldn't argue with price. I really like the car, and hope the engine doesn't make me regret this!
 

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Sounds like a nice car. Good luck with getting it sorted out as painlessly as possible. According to the diagrams above, relay B is the one I cleaned to cure my wiper problem.

Adios,
Mike
 

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Discussion Starter #8
Ok, so I drove the car home yesterday, and now I can poke around. I'm hoping my first success is an indicator of things to come. The number 17 fuse is in the windows and wiper circuit. I pulled the fuse- intact, but quite oxidized. The contacts in the fuse box are nice and clean, so in went a new fuse and eureka! The windows and wipers all work fine. I hope everything is this easy!
 
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