windows wont go down trouble shooting 85 300d - PeachParts Mercedes-Benz Forum

frankengrant · #1 09-19-2011, 05:14 PM

I'm trying to figure out what is going on with my windows, none of them will go down. All of the controls work, emergency lights, fader, mirror control... I got out my millimeter and tested the wire blocks leading into the switches. The only one with power, 12.1v, is the plug that goes into the rear windows unlock/ lock button. (the button between the front and rear driver side windows). When I pull off the wire blocks from the window switches themselves, none of the ones going to the windows have any power. Please help me, I'm burning up out here it is unbearable!

Thanks,

Grant

frankengrant · #2 09-19-2011, 05:47 PM

Btw, the fuses in the engine bay are all fine, checked visually and with my multimeter.

tangofox007 · #3 09-19-2011, 06:16 PM

Quote:

Originally Posted by frankengrant

The only one with power, 12.1v, is the plug that goes into the rear windows unlock/ lock button.

That's a ground circuit. There should not be power there unless a rear door window switch is actuated.

Loss of power to all windows could be a problem with the windows relay or its associated wiring to the key switch.

frankengrant · #4 09-19-2011, 07:04 PM

That's an ice box relay right? Like the one on the left front wheel well, that controls the ac? Is it the same part? Since I don't have ac, can I take the relay from that place and put it behind my instrument oanel to replace the window relay? What's the best way to get to that really in the panel? I dont have panel pulling tools.

tangofox007 · #5 09-19-2011, 08:32 PM

The relay is behind the instrument cluster, on the right side. I am not sure about commonality, esp on an '85. If you remove the lower dash panel, you can just push the instrument cluster out by reaching behind it.

frankengrant · #6 09-19-2011, 08:58 PM

They are the same part #, I pulled it from the engine bay, and pulled the lower kick panel, pushed out the cluster from behind, and replaced the relay....

THE WINDOWS WORK!!!!

Thanks so much for your help!

One problem though, the cluster lights aren't coming on now, nor is the buzzer when I leave my lights on, though the buzzer does come on when I insert the key... any ideas?

frankengrant · #7 09-20-2011, 02:36 AM

It was a blown fuse causing the lack of dash, and shifter lighting. I must have blown it when I was playing electrician earlier, everything is back to normal again!