Blower Motor Circuit

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: Blower Motor Circuit
- Blower Motor Circuit

DESCRIPTION

When the blower switch is set to position 1 or higher, the contact of the heater blower motor relay assembly is closed, current flows to the blower with fan motor sub-assembly, and the blower with fan motor sub-assembly operates. Operating the No. 2 heater control sub-assembly changes how the current flows to the motor through the resistors of the blower resistor, thereby changing the motor speed.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:
Inspect the fuses and relays for circuits related to this system before performing the following inspection procedures.

PROCEDURE

1. INSPECT HEATER BLOWER MOTOR RELAY ASSEMBLY

(a) Remove the heater blower motor relay assembly Removal.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

NG -- REPLACE HEATER BLOWER MOTOR RELAY ASSEMBLY Removal
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (HEATER BLOWER MOTOR RELAY ASSEMBLY - BATTERY AND BODY GROUND)

(a) Disconnect the C57 relay connector.

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

Standard Voltage:

Text in Illustration

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

3. CHECK HARNESS AND CONNECTOR (HEATER BLOWER MOTOR RELAY ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Disconnect the C57 relay connector.

(b) Disconnect the C32 amplifier connector.

(c) Disconnect the C21 heater control connector.

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

Standard Resistance:

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

4. INSPECT NO. 2 HEATER CONTROL SUB-ASSEMBLY

(a) Remove the No. 2 heater control sub-assembly Disassembly.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

NG -- REPLACE NO. 2 HEATER CONTROL SUB-ASSEMBLY Disassembly
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (NO. 2 HEATER CONTROL SUB-ASSEMBLY - BATTERY AND BODY GROUND)

(a) Disconnect the C21 heater control connector.

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

Standard Voltage:

Text in Illustration

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

6. INSPECT BLOWER RESISTOR

(a) Remove the blower resistor Disassembly.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

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

7. CHECK HARNESS AND CONNECTOR (BLOWER RESISTOR - NO. 2 HEATER CONTROL SUB-ASSEMBLY AND BODY GROUND)

(a) Disconnect the C27 resistor connector.

(b) Disconnect the C21 heater control connector.

(c) Disconnect the C26 motor connector.

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

Standard Resistance:

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

8. INSPECT BLOWER WITH FAN MOTOR SUB-ASSEMBLY

(a) Remove the blower with fan motor sub-assembly Disassembly.

(b) Apply battery voltage to the terminals and check that the blower with fan motor sub-assembly operates.

OK:

NG -- REPLACE BLOWER WITH FAN MOTOR SUB-ASSEMBLY Disassembly
OK -- Continue to next step.

9. CHECK HARNESS AND CONNECTOR (HEATER BLOWER MOTOR RELAY ASSEMBLY - BLOWER WITH FAN MOTOR SUB-ASSEMBLY)

(a) Disconnect the C57 relay connector.

(b) Disconnect the C26 motor connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

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

10. CHECK HARNESS AND CONNECTOR (BLOWER WITH FAN MOTOR SUB-ASSEMBLY - NO. 2 HEATER CONTROL SUB-ASSEMBLY AND BLOWER RESISTOR)

(a) Disconnect the C26 motor connector.

(b) Disconnect the C21 heater control connector.

(c) Disconnect the C27 resistor connector.

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

Standard Resistance:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Removal