ECM Compressor Control Test

ECM Compressor Control Test:

NOTE: This test is to be performed with the Ignition Switch in RUN (engine not running) and the Mode Selector in NORM.

1. Measure the voltage to ground at the terminals of the ECM shown in the above chart. Leave the connectors in place.

^ If Battery voltage is not present at terminal 6, remove the connector from the Power Steering Idle Speed Switch and make the following checks.

- If Battery voltage is now present, replace the Power Steering Idle Speed Switch.

- If Battery voltage is not present, check for short to ground in the LT BLU/ORN wire (495).

^ If Battery voltage is not present at terminal 21, check for an open in the DK GRN/WHT wire (459).

^ If Battery voltage is not present at terminal 7, check for an open in the DK BLU wire (1488). If wire is OK, replace the A/C Compressor Control Relay


2. Using a fused jumper, temporarily connect terminal 7 to ground.

^ If the A/C Cut-Out Relay operates and engages compressor clutch, the A/C wiring is OK. If compressor does not operate, condition is due to ECM. Refer to Powertrain Management/Computers and Controls/Testing and Inspection/Procedures. Testing and Inspection
^ If the A/C Cut-Out Relay does not operate or compressor does not turn on, replace the relay.