GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC Suburban - 4WD 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Heater Blower Controls System Check

Step

Action

Normal Result(s)

Abnormal Result(s)*

1
  1. Turn the ignition switch to RUN position.
  2. Rotate the HVAC control module blower switch through all speeds:
    3. • Low
    • Med 1
    • Med 2
    • High

The blower motor operates in all positions.

2

Turn the blower switch to the OFF position.

The blower motor shuts off.

Blower Motor Always On

3
  1. Turn the ignition switch to RUN position.
  2. Rotate the Auxiliary HVAC control module blower switch through all speeds:
    3. • Low
    • Med
    • High

The auxiliary blower motor operates in all positions.

4

Turn the auxiliary blower switch to the OFF position.

The auxiliary blower motor shuts off.

Auxiliary Blower Motor Always On

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.