Blower Motor Speed Control - Troubleshooting (Blower motor running speed does not change)
15-11flowchart1
Blower motor running speed does not change.
2
Disconnect the 4P connector from the blower resistor.
3
Check for continuity between the 2 and 4 terminals of the resistor.
4
Does continuity exist?
NO
Replace the resistor.
YES
5
Reconnect the 4P connector to the resistor.
6
Disconnect the 6P connector from the fan switch.
7
Turn the ignition switch on.
8
Measure voltage between: BLU/YEL terminal and body ground. BLU/WHT terminal and body ground. BLU terminal and body ground.
9
Is there battery voltage?
NO
Repair open in BLU/YEL, BLU/WHT and/or BLU wire(s) between the fan switch and resistor.
YES
10
Check for continuity from BLK terminal to body ground.
11
Is there continuity?
NO
Repair open in BLK wire between the fan switch and body ground or poor ground (G201).
YES
12
Replace the fan switch.