GM Service Manual Online
For 1990-2009 cars only

Battery positive voltage is supplied to the heated outside rearview mirror and rear window defogger relay K35 switch. Ignition positive voltage is supplied to the heated outside rearview mirror and rear window defogger relay K35 coil. The ground circuit of the heated outside rearview mirror and rear window defogger relay K35 coil is grounded by G103.

When the rear window defogger button is depressed. The heater and A/C control module energizes the heated outside rearview mirror and rear window defogger relay K35 by suppling battery positive voltage to the control circuit of the relay. This allows battery positive voltage to the heated mirrors. The ground circuit of the heated mirrors is grounded by G200.