Air Delivery Improper
Air Delivery Improper
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The HVAC control assembly applies voltage to the blower motor control circuit that corresponds to the selected blower speed. The resistors and the blower motor are in a series circuit. The following list represents the number of resistors in series with the blower motor per particular speed request:
* Low speed-3 resistors
* Medium 1 speed-2 resistors
* Medium 2 speed-1 resistor
When the operator requests High speed, the HVAC control assembly applies voltage to the blower motor through the high blower motor resistor assembly.
Circuit/System Verification
1. Ignition ON, mode set to the VENT position, place the blower switch in the LO, MED 1, MED 2 and HI speed positions. The blower motor should activate and operate from low to medium 1, medium 2, to high when changing between the commanded states.
^ If the blower motor speed does not change or fails to operate at a selected speed, refer to Auxiliary Blower Motor Malfunction (RPO C36) Auxiliary Blower Motor Malfunction (RPO C69 w/o Rear Controls) Auxiliary Blower Motor Malfunction (RPO C69 with Rear Controls). Auxiliary Blower Motor Malfunction (RPO C36) Auxiliary Blower Motor Malfunction (RPO C69 w/o Rear Controls) Auxiliary Blower Motor Malfunction (RPO C69 with Rear Controls)
2. Rotate the mode control switch from the OFF position to the VENT, BI-LEVEL, FLOOR, FLOOR/DEFROST and DEFROST positions. The air flow should follow the commanded states and blow through the vent, floor and defrost outlets.
^ If the air flow fails to blow through the selected outlets, refer to Vacuum Control System Diagnostic. Vacuum Control System Diagnostic