Blower Motor Circuit

AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Manual 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 (HTR)

(a) Remove the HTR fuse from the engine room No. 2 relay block.

(b) Measure the resistance of the fuse.

Standard resistance:

Below 1 Ohms

NG -- REPLACE FUSE
OK -- Continue to next step.

2. INSPECT HEATER RELAY (Marking: HTR)

(a) Remove the heater relay from the instrument panel junction block.

(b) Measure the resistance of the relay.

Standard resistance:

NG -- REPLACE HEATER RELAY
OK -- Continue to next step.

3. INSPECT BLOWER MOTOR

(a) Disconnect the E54 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:

NG -- REPLACE BLOWER MOTOR
OK -- Continue to next step.

4. CHECK WIRE HARNESS (HEATER CONTROL (BLOWER SWITCH) - BATTERY)

(a) Disconnect the E24 heater control connector.

(b) Measure the voltage of the wire harness side connector.

Standard voltage:

NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

5. INSPECT HEATER CONTROL (BLOWER SWITCH)

(a) Remove the heater control.

(b) Measure the resistance of the switch.

Standard resistance:

NG -- REPLACE HEATER CONTROL
OK -- Continue to next step.

6. INSPECT BLOWER RESISTOR

(a) Remove the blower resistor.

(b) Measure the resistance of the resistor.

Standard resistance:

NG -- REPLACE BLOWER RESISTOR
OK -- Continue to next step.

7. CHECK WIRE HARNESS (HEATER CONTROL (BLOWER SWITCH) - BLOWER RESISTOR)

(a) Disconnect the E24 heater control connector.

(b) Disconnect the E55 blower resistor connector.

(c) Measure the resistance of the wire harness side connectors.

Standard resistance:

NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

8. CHECK WIRE HARNESS (BLOWER RESISTOR - BLOWER MOTOR)

(a) Disconnect the E55 blower resistor connector.

(b) Disconnect the E54 motor connector.

(c) Measure the resistance of the wire harness side connectors.

Standard resistance:

NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

9. CHECK WIRE HARNESS (BLOWER MOTOR - BODY GROUND)

(a) Disconnect the E54 motor connector.

(b) Measure the resistance of the wire harness side connector.

Standard resistance:

NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

10. CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - BATTERY)

(a) Disconnect the E36 amplifier connector.

(b) Measure the voltage of the wire harness side connector.

Standard voltage:

NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

11. CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - BODY GROUND)

(a) Disconnect the E36 amplifier connector.

(b) Measure the resistance of the wire harness side connector.

Standard resistance:

NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE