Blower Motor Circuit

AIR CONDITIONING: AIR CONDITIONING SYSTEM: Blower Motor Circuit

Blower Motor Circuit

DESCRIPTION

When the heater control (blower switch) is set to position 1 or higher, the contact of the HTR relay is closed, current flows to the blower motor, and the blower motor operates. The blower motor speed can be changed by exchanging the ground and the blower resistor circuit with the heater control (blower switch).

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. INSPECT FUSE (GAUGE, HTR)
(a) Remove the GAUGE fuse from the main body ECU.
(b) Remove the HTR fuse from the engine room relay block.
(c) Measure the resistance.
Standard resistance:

(d) Reinstall the GAUGE fuse.
(e) Reinstall the HTR fuse.
NG -- REPLACE FUSE
OK -- Continue to next step.
2. INSPECT HTR RELAY

(a) Remove the HTR relay from the main body ECU.
(b) Measure the resistance.
Standard resistance:

(a) Disconnect the E4 blower motor connector.
(b) Connect the positive (+) lead from the battery to terminal 2 and the negative (-) lead to terminal 1, then check that the blower motor operates smoothly.
OK:
The blower motor operates smoothly.
(c) Measure the current.
Standard current:

(d) Reconnect the blower motor connector.
Result:

C -- REPLACE BLOWER MOTOR
B -- REPLACE BLOWER MOTOR
A -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (HTR FUSE - MAIN BODY ECU)

(a) Disconnect the 4L main body ECU connector.
(b) Measure the voltage.
Standard voltage:

(c) Reconnect the main body ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK MAIN BODY ECU

(a) Remove the HTR relay from the main body ECU.
(b) Measure the resistance.
Standard resistance:

(d) Reinstall the HTR relay.
(e) Measure the voltage.
Standard voltage:

NG -- REPLACE MAIN BODY ECU
OK -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - HEATER CONTROL (BLOWER SWITCH))
(a) Disconnect the E1 heater control (blower switch) connector.

(b) Measure the voltage.
Standard voltage:

(c) Reconnect the heater control (blower switch) connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BLOWER MOTOR)

(a) Disconnect the E4 blower motor connector.
(b) Measure the voltage.
Standard voltage:

(c) Reconnect the blower motor connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (BLOWER RESISTOR - BLOWER MOTOR)

(a) Disconnect the E3 blower resistor connector.
(b) Disconnect the E4 blower motor connector.
(c) Measure the resistance.
Standard resistance:

(d) Reconnect the blower resistor connector.
(e) Reconnect the blower motor connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
9. INSPECT BLOWER RESISTOR

(a) Remove the blower resistor.
(b) Measure the resistance.
Standard resistance:

C -- REPLACE BLOWER RESISTOR
B -- REPLACE BLOWER RESISTOR
A -- Continue to next step.
10. INSPECT HEATER CONTROL (BLOWER SWITCH)

(a) Remove the heater control (blower switch).
(b) Measure the resistance.
Standard resistance:

(c) Reinstall the heater control (blower switch).
NG -- REPLACE HEATER CONTROL
OK -- Continue to next step.
11. CHECK HARNESS AND CONNECTOR (HEATER CONTROL (BLOWER SWITCH) - BLOWER RESISTOR)

(a) Disconnect the E1 heater control (blower switch) connector.
(b) Disconnect the E3 blower resistor connector.
(c) Measure the resistance.
Standard resistance:

(d) Reconnect the heater control (blower switch) connector.
(e) Reconnect the blower resistor connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (BLOWER RESISTOR - BODY GROUND)