Circuit/System Description
WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
Auxiliary HVAC Control Module
The front HVAC control module must be in the ON position for GMLAN communication to allow the rear HVAC control module to operate.
Auxiliary Blower Motor Control Module
The following are auxiliary blower motor control module circuits:
- Rear blower motor speed control circuit-When the auxiliary blower switch is placed in any speed position this circuit is a pulse width modulated signal that is sent from the Auxiliary HVAC control module to the auxiliary blower motor control module.
- Ground-A constant body ground is supplied to the auxiliary blower motor control module.
- Low reference-This circuit is grounded through the auxiliary blower motor control module only when the auxiliary HVAC control module is in high speed. In all other blower speeds this circuit is a pulse width modulated signal (PWM). The longer this circuit is pulsed the ground the faster the blower speed will be.
- Blower speed feed back signal-This feedback circuit displays in percent on the TECH 2 the commanded output blower speed that the auxiliary blower motor control module is sending to the auxiliary blower motor.
Auxiliary Blower Motor
The following are auxiliary blower motor circuits:
- Ground-A constant body ground is supplied the blower motor.
- Ignition voltage-Ignition voltage is supplied to the blower motor from the rear fuse box.
- Low reference-This circuit is grounded through the auxiliary blower motor control module only when the auxiliary HVAC control module is in high speed. In all other blower speeds this circuit is a pulse width modulated signal (PWM). The longer this circuit is pulsed the ground the faster the blower speed will be.