Blower Motor Control Inspection (Does Not Work at All)

Blower Motor Control Inspection (Does Not Work At All)
If the blower motor does not operate at any speed, the failure is in the following devices or related wiring harness.
1. Blower motor
2. 0FF relay
3. A/C amplifier






Step 1
Fuse Inspection








1. Check the indicated fuses.
2. If a fuse is burnt, replace it after checking and repairing the wiring harness as necessary.
3. If the fuses are OK, go to Step 2.

Step 2
Heater Relay Inspection
1. Remove the off relay.





2. Connect battery positive voltage to terminal d and ground terminal c.





3. Check continuity between terminals a and b of the relay.


Step 3
Heater Relay Inspection





1. Connect a jumper wire between terminal wire (P/B) of the off relay connector and a body ground.
2. Turn the ignition switch ON and press the AUTO switch ON.
3. If the blower motor does not operate, go to Step 5.
4. If the blower motor operates, go to Step 4.


Step 4
Harness Continuity Inspection
1. Disconnect the off relay connector and A/C amplifier connector.








2. Check for continuity of terminal wire (P/B) between the connectors.


Step 5
Blower Motor Connector Terminal Voltage Inspection
1. Connect a jumper wire between terminal wire (P/B) of the heater relay connector and a body ground.
2. Turn the ignition switch ON and press the AUTO switch ON.








3. Measure voltage at terminal wires (R) and (L/W) of the blower motor connector.


Step 6
Power Transistor Terminal Voltage Inspection





1. Connect a jumper wire to the terminal wire P/B of the heater relay connector and a body ground.
2. Turn the ignition switch ON, and turn the AUTO switch ON.





3. Measure voltage at terminal wire (LW) of the power transistor connector.


Step 7
Harness Continuity Inspection








- Check for continuity between terminal wire (B) of the power transistor connector and a body ground.