Blower Motor Circuit

AIR CONDITIONING: AIR CONDITIONING SYSTEM: Blower Motor Circuit

Blower Motor Circuit

DESCRIPTION

When the No. 2 heater control (blower switch) is operated, the HTR relay will turn on to allow current to flow to the blower motor and then the motor will start rotating. Operating the No. 2 heater control (blower switch) switches the current flow between the blower resistor and body ground, thus, shifting the rotation speed of the blower motor.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. INSPECT FUSE (HTR, ECU-IG NO. 2)

(a) Remove the HTR fuse from the engine room relay block.
(b) Remove the ECU-IG No. 2 fuse from the main body ECU.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:

(d) Reinstall the HTR and ECU-IG No.2 fuses.
NG -- REPLACE FUSE
OK -- Continue to next step.
2. INSPECT RELAY (HTR)

(a) Remove the HTR relay from the main body ECU.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:

(c) Reinstall the HTR relay.
NG -- REPLACE HTR RELAY
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY)

(a) Disconnect the C8 A/C amplifier connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:

(c) Reconnect the A/C amplifier connector.
NG -- INSPECT BLOWER MOTOR
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
4. INSPECT BLOWER MOTOR

(a) Remove the blower motor.
(b) Connect the positive (+) lead from the battery to terminal 2 and negative (-) to terminal 1, and check that the motor operates.
OK:
The blower motor operates smoothly.
NG -- REPLACE BLOWER MOTOR
OK -- Continue to next step.
5. INSPECT BLOWER RESISTOR

(a) Remove the blower resistor.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:

(c) Reinstall the blower resistor.
NG -- REPLACE BLOWER RESISTOR
OK -- Continue to next step.
6. INSPECT NO. 2 HEATER CONTROL (BLOWER SWITCH)

(a) Remove the No. 2 heater control (blower switch).
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:

(c) Reinstall the No. 2 heater control (blower switch).
NG -- REPLACE NO. 2 HEATER CONTROL
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY)

(a) Disconnect the C8 A/C amplifier connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:

(c) Reconnect the A/C amplifier connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (NO. 2 HEATER CONTROL (BLOWER SWITCH) - BATTERY)
(a) Disconnect the C40 No. 2 heater control (blower switch) connector.

(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:

(c) Reconnect the No. 2 heater control (blower switch) connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
9. CHECK HARNESS AND CONNECTOR (BLOWER RESISTOR - NO. 2 HEATER CONTROL (BLOWER SWITCH))

(a) Disconnect the C21 blower resistor connector.
(b) Disconnect the C40 No. 2 heater control (blower switch) connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:

(d) Reconnect the blower resistor connector.
(e) Reconnect the No. 2 heater control (blower switch) connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
10. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BLOWER RESISTOR, NO. 2 HEATER CONTROL)
(a) Disconnect the C19 blower motor connector.
(b) Disconnect the C21 blower resistor connector.
(c) Disconnect the C40 No. 2 heater control (blower switch) connector.

(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:

(e) Reconnect the blower motor connector.
(f) Reconnect the blower resistor connector.
(g) Reconnect the No. 2 heater control (blower switch) connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
11. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY, BODY GROUND)
(a) Disconnect the C19 blower motor connector.

(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:

(d) Reconnect the blower motor connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK INTERMITTENT PROBLEMS