CODE B445, A/C COMPRESSOR ENGAGE CIRCUIT (Cont.): Notes

It has been determined by the previous chart that the problem is in the circuitry of the winding side of the relay. This determination was made when the test light was put in place of the relay windings during output function EO08, and the test light did not cycle on and off.

1. Checks to see if the fault is due to a circuit problem to the relay or a circuit problem to the power module that controls the relay.
2. Checks to see if the fault is due to ground side circuitry or control side circuitry for the power module. Since the climate control blower shares the same ground to the power module, if the fan does not work, the ground circuit is at fault (including terminal contact and power module).
3. By checking voltage at various points, it can be determined if the control signal circuit, the ECM, or the power module is at fault.
4. Checks to see if the fault is due to an open in feed to relay winding or ground (control signal) to relay winding.