Blower Motor: Testing and Inspection

Checking Blower Motor:

BLOWER MOTOR RESISTANCE
1. Disconnect the harness connector from the blower motor.
2. Using an ohmmeter, measure resistance between terminals [a] and [b]. Fig. A Resistance should be:

Approximately 0.1-0.2 Ohms

3. If resistance is not within specifications, check the blower motor, harness, and connections. Repair or replace as necessary and recheck.

BLOWER MOTOR OPERATION
1. Disconnect the harness connector from the blower motor.
2. Connect positive battery lead to terminal [a] and negative lead to terminal [b]. Fig. B
3. Blower motor should operate.
4. If blower motor does not operate, check the blower motor, harness, and connections. Repair or replace as necessary and recheck.

CHECKING POWER TRANSISTOR
1. Make test circuit as shown in Fig. C.
2. Measure voltage between terminals [a] and [b] and current IC applying power source. Readings should be as follows:

SW1 OFF
IC Less than 10 mA

SW1 ON
Voltage more than 3 VDC

3. If readings are not within specifications, replace power transistor.