Cavalier/Z24 V6-191 3.1L VIN T MFI (1994)
Blower Motor: Initial Inspection and Diagnostic Overview
Troubleshooting Hints
TRY THE FOLLOWING CHECKS BEFORE DOING THE SYSTEM CHECK
1. Check HTR-A/C Fuse by visual inspection.
2. Check Fusible Link B by visual inspection.
3. Check that ground G100 is clean and tight.
4. Check that the Blower Motor connectors and Blower Motor Relay are mated correctly and firmly seated.
5. If blower runs all of the time with Ignition Switch OFF, replace the Blower Motor Relay.
6. If blower runs all of the time with the Ignition Switch in RUN and the Mode Selector OFF replace the Mode Selector.
7. Replace the Mode Selector if the Blower Motor runs with the Ignition Switch in RUN and the Mode Selector in one but not all of the following
modes: MAX, VENT, BI-LEV, HTR, BLEND and DEF.
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Go to HVAC System Check on for a guide to normal operation. See: Testing and Inspection
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Go to System Diagnosis for diagnostic tests. See: Air Conditioning/System Diagnosis
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Refer to Heater-A/C and Windows and Glass for Rear Defogger Control Assembly access information. See: Windows and Glass/Heated Glass
Element
System Diagnosis
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Refer to Symptom Table for listed symptoms and refer Diagnostic Tests for Diagnostic procedures. See: Symptom Related Diagnostic
Procedures/Air Conditioning See: Component Tests and General Diagnostics/Air Conditioning
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If your symptom does not appear in the Symptom Table, perform all of the tests.
Circuit Operation
The Blower Motor's speed is controlled by the Blower Switch in the Heater-A/C and Rear Defogger Control Assembly. With the switch in the LO
position, all of the Blower Resistors are in the circuit with the motor so that it runs slowly. In the M1 and M2 positions, the Blower Switch bypasses
some of the resistors, increasing the motors speed.
The Blower Motor is fed through the contacts of the Blower Motor Relay. When the Blower Switch is in the HI position, battery voltage is supplied
through the ORN wire to the coil of the Blower Motor Relay. The relay is energized and its contact supplies battery voltage directly to the Blower Motor
from Fusible Link B.
When the Mode Selector is in the OFF position, no voltage is applied to the Blower Switch and Motor, so the blower does not run. In all other positions,
the blower should operate as described.
Circuit Operation
The Blower Motor delivers air to the interior of the vehicle. Its speed is controlled by the Blower Switch and the Blower Resistor Assembly. When the
Ignition Switch is in RUN, battery voltage is applied to the Mode Selector. With the Mode Selector in any position except OFF, voltage is then supplied
to the Blower Switch. With the Blower Switch in LO, voltage is applied across all the Blower Resistors and the Blower Motor; the Blower Motor runs at
its slowest speed. With the Blower Switch in M1, one of the Blower Resistors is bypassed; the Blower Motor runs faster. When Blower Switch is in M2,
two of the Blower Resistors are bypassed; the Blower Motor runs faster. When the Blower Switch is set to HI, the Blower Resistors are totally bypassed
and battery voltage is applied directly to the Blower Motor; the Blower Motor runs at its fastest speed.
System Check