so as the title says my rear defrost dosen't work and I've finally found the motivation to fix it. the grid is good, the switch seems to be good and power is getting to the switch (only on one prong though). all the fuses under the dash are good; however I think I read somewhere that the defroster is fused in a different location. anyway where should I go from here???

yeah I know I haven't posted in a while but I've been searching and lurking

 

bump

 

sorry I cant help you, but what do you men by the defroster is fused somewhere else? maybe that is my issue as well.

 

power comes from the power accesory circuit breaker and the gauge fuse.

 

If you remove the piece of dash with the defroster switch, you'll see a 6-prong connector on it with 5 wires. Check the following wires:
- orange/black - should have 12V on it at all times
- pink/black - should have 12V with key on
- gray - should have 12V with lights on (doesn't matter right now)
- blk - should be grounded at all times (measure against 12V)
- purple/white - should seem like it's another ground (measure against 12V again)

If all this checks out, follow below:
- key off - confirm that the purple/white wire shows 12V if you measure it against 12V. If not, the circuit to the defogger is bad.
- key on - confirm that the purple/white gets 12V when you activate the defogger. If not, the module is bad.
- key on - activate the defogger and confirm that the ON indicator is lit. If not, the module might be bad.

Let us know what you find.

Hope this helps.
Lou

 

Hello, I have similar problem. Rear defroster doesn't work.. I pulled the switch and wire colors are as above except there is no orange wire. Instead I have a light blue one. I did have juice coming from the pink and black. (no longer as in playing around and trying to jump juice without the switch I blew a fuse somewhere). All the wiring diagrams I have found show only an orange wire. Has anyone seen one with a light blue??
If I know which wire to put juice to I can get defroster to work with a jumper wire till spring..
The car is an 83 TA 5.0 eng. (Bought the car new so I know the wire has not been just switched out for another color).
Any help is appreciated. Frosted over windows are a daily thing up here in Alaska!!

 

Also check the connectors attached to the hatch dampers. I've had one work loose before.