Rear Defroster - Troubleshooting Advice

[dapplestein]

I have an '80 Euro SC on which the rear electric defroster doesn't work. Would appreciate some help on how to troubleshoot it. Thought the first thing would be the make sure power was getting to the dash switch and that the switch was working. Next thing, would be to check out the rely in the engine bay but don't know how to check out the rely to make sure it is working. Assuming I get through that, thought the next thing would to make sure power is getting to the grid enbedded in the window. How can I do that? Any advise/suggestions are appreciated. Thank.

Don

[autobonrun]

It's a different electrical circuit, but I briefly discussed how to check out a relay here:

Very Frustrated. Electrical experts required please.

[Mark McClure]

OK...I have done this. I had a car that did not have a switch but all the wiring and relay was in place.......First question has it ever worked?

So.......first check to see if the switch has power and that the switch works. If it is the three stage switch then you have one which pulls out and then turns two notches. I understand that this is for the heated front screen and the two stage rear. Either way make sure that each stage operates properly.

Next go to the relay, it is the large rectangular silver gray one. you can remove this and bend the case clips to remove the cover. Inside you will find either one or two solenoids. Meter out the feed wire to see if power is getting to the solenoids when the switch is on. Normal problem solving at this point.....if no power then it has to be the wiring between front and back. (I actually ran new wires, it was a lot easier for me). A common problem with solenoides is the contacts. If the solenid is pulling it brings two connections together. These can sometimes become blackened due to arcing. Clean these with a piece of emmery paper. If the contact do not meet when the solenoid pulls then bend the contact slightly.

How does that sound.....

Cheers

Mark......