[jcommin]

On the early cars, 3 out of the 4 switches were used.

(1) Rear wiper
(1) Head light washer
(1) Blank - rear fog light not an option back in 83.
(1) Activates the right of left mirror - to use the mirror adjustment ball on the dirver's door.

The rear defroster switch(next to the hazzard light on the dash). There is a fuse and a relay for the rear defroster. The light on the switch only indicates that the switch is in the 'on' position. It doesn't know whether or not the defroster is working.

Things to check:

The relay, located with the rest on the relays - see owners manual.
The LH hatch shock - Using a multi meter, check the conductivity between at the ends. If you get nothing, replace the shock. Check the connections at the grid. You should get conductivity.

Finally, print out the article on the Clarks Garage Web site about the rear defroster. It will tell you how to troubleshoot the defroster. You will need a multimeter for this. You might have a bad ground.