PeachParts Mercedes-Benz Forum - View Single Post - Power windows and blower fan stopped working

Jeremy5848 · #7 12-23-2007, 06:05 PM

Quote:

Originally Posted by Bootsy1313

Jeremy,

Yes, the fan does not come on, but when I hit the buttons for the other functions like heater or defrost, I don't hear anything moving (flaps, whatever), so I don't know if it is JUST the blower.

I just checked the grounds behind the cluster,; there sure are a lot of 'em, but it looks good, no corrosion, nice and tight, no (obviously) broken wires.

And yes, ALL the power windows don't work...

Any other grounds I should check? Is there something I should do besides pulling on the wires to make sure they are not broken?

Thanks

This might be two separate problems that occurred at the same time by coincidence (windows and ACC). Coincidences happen all the time, although we must always be suspicious of them, in case they do turn out to be related somehow.

If the fan and flaps both do not work, the problem is likely electrical. I don't remember whether the '83 has the latest version of Climate Control or one of the older versions -- perhaps someone else can help here. The flaps are controlled by vacuum actuators and the actuators by the ACC controller, which is electric, so both must work.

If nothing works, then the ACC controller is not getting electricity. You checked the fuses but there could also be a broken wire or (more likely) a failure of the Climate Control electronics (the thing with the pushbuttons). The ACC controller also needs vacuum, which comes from the engine-mounted vacuum pump. If the power brakes work, then the vacuum pump is OK but there could be a broken or leaking vacuum line somewhere, especially given the age of the car.

Defrost is the "default" for the Climate Control system -- the rationale being that getting hot air to clear a fogged or iced window contributes most to safety. Even if all of the vacuum flap actuators fail you should get hot air onto the windshield if the ACC controller is getting electricity.

The Climate Control system includes an auxiliary water pump, which assists in getting sufficient hot coolant into the heater when the engine is turning slowly (as in city traffic). Unfortunately, Mercedes failed to fuse this little (electric) water pump; if it freezes, it draws too much current and damages the printed-circuit wiring in the ACC (pushbutton) module. Rebuilt modules are available (I was able to repair my own) and everyone is encouraged to add a fuse to the aux pump circuit to prevent a recurrence of this failure. The later (W124) cars have a current-limiting circuit built in to prevent this problem.

You can test the ACC blower separately. Remove the passenger kick panel and you will find the blower up underneath, with a two-wire black plastic plug and cable. Remove the plug and put 12 Volts directly on the motor terminals to see if the blower will work. The blower is held in with three screws and is fairly easy to remove.

As for the windows, there may be a ground in the area of the console where the window switches are located. You can lift up the panel with the switches to check on the ground. If you have a voltmeter, you can also see if the switches are getting 12 Volts.

To remove the window switch panel, you must remove a screw or screws located at the front or back of the panel (I don't remember which year-model has which fastening). To get at a screw at the back of the panel, you lift up and remove the little piece of carpeting that lives at the bottom of the tray. To access the screws in front, you remove the ashtray. With the screws out, you can pull the panel back and up gently.

Jeremy