Principle of Operation

The GM controls the lock heater by providing voltage through a final stage transistor. The heater is switched on by raising the driver's door handle. Prerequisites for heater operation include:

• Vehicle locked.
• Door handle raised for approximately 3 seconds.

Power is applied to the heater for a maximum of 32 seconds. A timed arrest of 16 minutes is activated after 3 heating attempts. The door lock heater is switched off immediately after unlocking the door.