Component Diagnostic Charts/Tests

Fig. 019 Chart C-10-A A/C Clutch Control:

Fig. 020 Wiring Diagram for C-10-A A/C Clutch Control:

CHART C-10-A

A/C CLUTCH CONTROL

2.0L OHC (VIN K) "J" SERIES

2.5L "A, N & P" SERIES

FUEL INJECTION (TBI)




Circuit Description: When an A/C Mode is selected on the A/C control switch, ignition voltage is supplied to the compressor low pressure switch. If there is sufficient A/C refrigerant charge, the low pressure switch will be closed and complete the CKT to the closed high pressure cut-off switch and to CKTs 67 and 459. The voltage on CKT 459 to the ECM is shown be the "Scan" tool as A/C request "ON" (voltage present), "OFF" (no voltage). When a request for A/C is seen by the ECM, the ECM will ground CKT 458 to CKT 59 and engage the A/C compressor clutch. A "Scan" tool will show the grounding, or CKT 458, as A/C clutch "ON". If voltage is seen by the ECM on CKT 67, the cooling fan will be turned on.



Diagnostic Aids:
Both pressure switches are located on the high side of the A/C System. The low pressure switch will be closed at 40-47 psi and allow A/C clutch operation. Below 37 psi, the low pressure switch will be open and the A/c clutch will not operate.
At about 430 psi, the high pressure switch will open to disengage the A/C clutch and prevent system damage.