Chevette Defroster wiring harness
(under dash )
Please note the defroster wiring harness depicted above. This is how it looks as it comes out from under the dash of the Chevette. I removed this from a 1981 Chevette that had air conditioning. That added some complexity to the job, as the A/C ducting has to be gotten out of the way. Fortunately, that is rather simple. You must remove the panel under the steering column also to get to this wiring.
Starting from the top left, note the large pink wire which goes to the starter. This is a large 10ga wire that has a fusible link. It bolts from the starter to a circuit breaker. The circuit breaker is bolted to the inner fender panel, drivers side, directly in front of the maze of wires which is the Computer Command Control System wiring, near the hood hinge.
From the circuit breaker, an orange wire goes through the bulkhead via a rubber grommet. I advice pushing the orange wire/grommet assembly through the bulkhead INTO the car. This will keep the complete underdash harness intact.
There is a small black wire that bolts to the inner kick panel metal. A heavy pinkish wire, with an extra power connector plugs directly into the fuse block.
A VERY large 10ga wire runs to the back, along the drivers side door sill. It is encased in a black sheath, along with other wires, if applicable.
The rest of the underdash harness is wrapped in black electrical tape. It travels up the dash, above the steering column, right behind the instrument cluster. The first connector attaches to the defroster switch. The next connector attaches to the defroster timer. The Timer is a large silver box that is bolted to the bulkhead panel, behind the air conditioning ducting, above the carpet, on the passenger side. It is rather buried.
That completes the inside car/underdash wiring of the rear window defroster. The large purple wire that goes to the rear window travels along the drivers side door sill, back to the rear drivers side sail panel, and up it where is connects to a retainer near the plug on the rear window grid. The wire that goes from the rear sail panel to the window is braided wire, encased in flexible plastic. It is flexible to withstand opening and closing of the hatch. On the opposite side the hatch has a ground wire attached to the passenger side sail panel.
SOOOooooooo.... all you have to do to install a rear window defroster into a car that originally didn't have one, is round up all the stuff above, a hatch with defroster grid, and you're in business ! Nothing to it !
Except for installing it under the dash !