GM Service Manual Online
For 1990-2009 cars only

B+ is supplied to terminal 2 of the heated outside rear view mirror and rear window defogger relay K35 at all times. B+ is supplied to terminal 1 of the heated outside rear view mirror and rear window defogger relay K35 when the ignition switch is in the ON position. Ground is supplied to the heated outside rear view mirror and rear window defogger relay K35 at all times through G103.

When the rear window defogger switch is pressed, B+ is input into terminal 4 of the heated outside rear view mirror and rear window defogger relay K35. This energizes the relay and B+ is supplied to the input side of fuse #11. Fuse #11 then supplies B+ to the LH and RH outside rear view mirrors for as long as the defrost cycle is ON. The heating element within the LH and RH mirrors warms up and defrosts the mirrors. The LH and RH outside rear view mirrors are permanently grounded to G200.