C: ECM Compressor Control Test

1. Reconnect the A/C Cut-Out Relay. Remove the connectors from the ECM and check the voltage to ground using a test lamp at the following terminals.

^ If test is correct, proceed to step 2.

^ If test lamp does not light at Terminal C9 repair open in the LT BLU (67) wire.

2. Connect Terminal C15 of ECM connector C3 (see schematic) to ground with a fused jumper.

^ If A/C Compressor Control Relay operates and turns on the compressor, the compressor control wiring is good. Refer to Computers and Control Systems for ECM diagnostics. Computers and Control Systems

^ If the A/C Cut-Out Relay does not operate or the compressor does not turn on, check the LT GRN/BLK (366) wire for an open If wire is good, replace the A/C Cut-Out Relay.