GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC C Pickup - 2WD 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Heater Blower Controls Component Views
Figure 1:

Auxiliary Heater Wiring
Object Number: 372173 Size: MF
(1)Auxiliary Blower Resistor
(2)Auxiliary Blower Relays; Low/Medium/High
(3)Auxiliary Blower Motor Connector
(4)C401
(5)Front to Rear Body Harness
(6)C400
(7)Auxiliary Blower Motor
Figure 2:

Rear Heater Fan Switch
Object Number: 331841 Size: MF
(1)Rear Fan Switch Connector
(2)Rear Fan Switch
Figure 3:

HVAC Control Module (Rear View)
Object Number: 376153 Size: MF
(1)Dash
(2)HVAC Control Module Connector, C1
(3)HVAC Control Module Connector, C2
(4)IP Harness
(5)HVAC Control Module Connector, C3
(6)HVAC Control Module (Rear View)
Figure 4:

Front HVAC Assembly
Object Number: 372168 Size: MF
(1)Blower Resistor
(2)Blower Motor
(3)Blower Motor Connectors
(4)C230
(5)C203
(6)C204
(7)Temperature Door Motor
(8)HVAC Plenium
(9)Mode Door Motor
(10)HVAC Wiring Harness
(11)Blower Motor Relay, High