Air Conditioning Relay

Air Conditioning Circuit:

To test the Air Conditioning Relay, located in the engine compartment, proceed as follows.


COMPONENT TEST
1. Remove the A/C relay.
2. Using an Ohm meter, check for continuity between terminals 2 and 4.

Continuity
Should exist

3. Apply 12vdc across terminals 2 and 4 of the relay.
4. Using an Ohm meter check for continuity between terminals 1 and 3.

Continuity
Should exist


HARNESS TEST
1. Using a Volt meter, check for Voltage between harness terminal 3 of the A/C relay and ground.

Voltage
System Voltage

2. Turn the key, A/C and blower switches to the ON position and check for Voltage at harness terminal 4 of the A/C relay.

Voltage
System Voltage

3. Turn the key to the OFF position and disconnect the ECU connectors.
4. Using an Ohm meter check for continuity between ECU harness terminal 65 and relay harness terminal 2.

Continuity
Should exist


If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed, confirm that the repair has corrected the problem.

If the trouble returns, it is possible that there is an intermittent failure of the component or the ECU. Check for looseness at all harness junctions and test for an intermittent failure.



Operation


The air conditioning switch applies battery Voltage to the engine control module when the air conditioning is switched ON.

When the air conditioning signals are input, the engine control module activates the idle air control motor, and also switches ON the power transistor. As a result, current flows to the A/C compressor clutch relay coil and the relay switch is switched ON, the air conditioning compressor's magnetic clutch is activated.


Troubleshooting Hints

If the air conditioning compressor's magnetic clutch is not activated when the air conditioning switch is switched ON during idling, it is probable that the cause is a malfunction of the air conditioning control system.




Inspection




Harness Inspection