HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS) > Diagnostics for A/C System Malfunction

BLOWER FAN DOES NOT ROTATE

TROUBLE SYMPTOM:

• Blower motor does not rotate.

• Blower motor does not change speeds.

WIRING DIAGRAM:

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1.CHECK FUSE.

1) Remove fuse No. 22, 27 and 28 from fuse & relay box.

2) Check the condition of fuse.

Is any fuse blown out?

Replace the fuse.

2.CHECK POWER SUPPLY OF BLOWER MOTOR RELAY.

1) Turn the ignition switch to OFF.

2) Remove the blower motor relay.

3) Turn the ignition switch to ON.

4) Turn the blower fan switch to ON.

5) Measure the voltage between terminals using a tester.

Connector & terminal

(B386) No. 2 (+) — Chassis ground (−):

Is the voltage 10 V or more?

Repair the open circuit of blower motor power supply line harness.

3.CHECK POWER SUPPLY OF BLOWER MOTOR RELAY.

Measure the resistance between terminals using a tester.

Connector & terminal

(B386) No. 2 (+) — (B386) No. 4 (−):

Is the voltage 10 V or more?

Replace the blower motor relay.

4.CHECK HARNESS.

1) Turn the ignition switch to OFF.

2) Remove the A/C control panel.

3) Measure the resistance between the control panel and relay using a tester.

Connector & terminal

(B386) No. 4 — (i88) No. 9:

Is the resistance less than 10 Ω?

5.CHECK POOR CONTACT.

Check for poor contact of the A/C control panel connector.

Is there poor contact in connector?

Repair the connector or replace the harness.

Replace the auto A/C control module.

6.CHECK BLOWER MOTOR RELAY.

1) Connect blower motor relay terminal No. 2 to the battery positive terminal, and No. 4 to the battery negative terminal.

2) Measure the resistance between terminals using a tester.

Connector & terminal

(Relay) No. 1 — No. 5:

Is the resistance less than 10 Ω?

Replace the blower motor relay.

7.CHECK BLOWER MOTOR POWER SUPPLY.

1) Install the blower motor relay and control panel.

2) Turn the ignition switch to ON.

3) Turn the blower fan switch to ON.

4) Measure the voltage between the blower motor and chassis ground using a tester.

Connector & terminal

(B87) No. 2 — Chassis ground:

Is the voltage 10 V or more?

Repair or replace the harness between the relay and blower motor.

8.CHECK BLOWER MOTOR.

1) Disconnect the connector from the blower motor.

2) Connect the battery positive terminal to terminal No. 2 of blower motor connector, and negative terminal to terminal No. 1.

3) Make sure the blower motor runs.

Does the blower motor run?

Replace the blower motor.

9.CHECK HARNESS.

1) Turn the ignition switch to OFF.

2) Disconnect the blower motor connector and power transistor connector.

3) Measure the resistance between the blower motor and power transistor using a tester.

Connector & terminal

(B87) No. 2 — (B57) No. 4:
(B87) No. 1 — (B57) No. 3:

Is the resistance less than 10 Ω?

Repair or replace the harness.

10.CHECK HARNESS.

Measure the resistance between the power transistor and chassis ground using a tester.

Connector & terminal

(B57) No. 1 — Chassis ground:

Is the resistance less than 10 Ω?

Repair or replace the harness.

11.CHECK HARNESS.

1) Turn the ignition switch to OFF.

2) Remove the control panel.

3) Measure the resistance between the control panel and power transistor using a tester.

Connector & terminal

(i88) No. 40 — (B57) No. 2:

Is the resistance less than 10 Ω?

Repair or replace the harness.

12.CHECK POOR CONTACT.

Check for poor contact of the A/C control panel connector.

Is there poor contact in connector?

Repair the connector or replace the harness.

13.CHECK FAN CONTROL SIGNAL.

1) Connect the removed connector(s).

2) Turn the ignition switch to ON.

3) Change the fan dial from 1st to 7th.

4) Measure the voltage between the power transistor and chassis ground using a tester.

Connector & terminal

(B57) No. 2 — Chassis ground:

Is voltage approx. 10 V when in 1st and approx. 1 V when in 7th?

Replace the power transistor.

14.CHECK POOR CONTACT.

Check for poor contact of the A/C control panel connector.

Is there poor contact in connector?

Repair the connector or replace the harness.

Replace the auto A/C control module.