A/C Compressor Control Test

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

1. Measure the voltage to ground at terminals C and E of the A/C Control Head. Leave the connector in place.

Terminal (Wire Color) Voltage
E (BRN) Battery
C (LT GRN) Battery

^ If voltages are correct, proceed to Step 2.
^ If voltage at terminal E is incorrect, check the HTR-A/C Fuse. If fuse is good, check for an open to the BRN wire (50).
^ If voltage at only terminal C is incorrect, replace the A/C Control Head.

2. Check the condition of the A/C Pressure Cycling Switch as follows:

^ Remove the connector from each switch and connect a fused jumper between the terminals of the connector.
^ If the switch is open, Battery voltage will be present at the A/C Cut-Off Relay when the jumper is connected (terminal B).
^ If the A/C Low Pressure Cut-Out or A/C Pressure Cycling Switch is open, check for proper refrigerant charge. If charge is OK replace switch.
^ If all the switches are OK, check the wiring between switches for an open.