Chart C-10C A/C Cutout Relay

Fig. 002 - Wiring Diagram for Chart C-10C A/C Cutout Relay.:

CHART C-10C,A/C CUT-OUT RELAY

The A/C cut-out relay is designed to disengage the A/C compressor clutch during hard acceleration and momentarily during engine start-up on a warm motor. The relay is ECM controlled. The relay coil is supplied 12 volts from the A/C power feed circuit, and the ECM completes the ground to open a set of normally closed points. This turns the compressor clutch "OFF." The ECM completes the ground circuit when a high TPS voltage (Wide Open Throttle) is sensed or an engine run signal is sensed with coolant temperature above a given amount. This delayed engagement on start-up is only for about 3 seconds.

Fig. 001 - Chart C-10C A/C Cutout Relay.:

1. Checks for normal A/C clutch operation at idle. If the clutch is not "ON," make certain the other A/C components are OK such as proper belt tension, sufficient freon charge, A/C fuse not blown prior to checking relay.
2. Checks for normal A/C clutch cut-out during WOT. If the compressor disengages, the system is OK. Clear long term memory.
3. By jumping across the relay coil connector terminals, it can be determined if the compressor remained engaged from a faulty relay (light "ON") or from lack of signal to energized coil to open the relay points (light "OFF").
4. By jumpering across relay contact point's connector terminals, it can be determined if lack of compressor operation is due to open relay contact points. If compressor engages, fault is in the relay or false (ground) signal from ECM circuit to disengage compressor clutch at wrong time.
5. Checks to see if "open" is in clutch coil (light "ON") or in clutch coil circuits (light "OFF"). If the test light is "OFF," there is either an open in 12-volt power feed to clutch coil or to ground from clutch coil.