Code .8.0 Air Conditioner Clutch Circuit

Fig. 34 Compressor clutch wiring circuit:

When the air conditioner clutch is operating, the ECC programmer sends a 12 volt signal to the ECM so that the ECM can compensate for the added air conditioner load placed on the engine. Trouble code .8.0 indicates that the ECM is not receiving the 12 volt signal from the programmer when the air conditioner clutch is activated.
1. With engine running, and ECC set at 60, enter diagnostics.
2. Check operation of clutch by pressing and releasing the ``outside temp.'' button. With button released, the ``A/C clutch'' status light will illuminate. Depressing the button will turn the light off. The clutch should engage with the light on and disengage when the light is off. If clutch does not operate properly, make necessary repairs to air conditioning system. If clutch operates satisfactorily, proceed as follows:
a. With ``A/C clutch'' status light off, check voltage at pin 21 of red ECM connector.
b. If no voltage is recorded, repair open in circuit 977 between power module and ECM.
c. If voltmeter reads 12 volts, the ECM or ECM connector is at fault. Repair or replace as necessary.