Chart C-10B A/C Wide Open Throttle (WOT) Relay Check

Fig. 047 - Wiring Diagram for Chart C-10B A/C Wide Open Throttle (WOT) Relay Check.:

CHART C-10B

A/C W.O.T. RELAY CHECK

3.0L "A, C" SERIES

CARBURETED

The A/C Wide-Open Throttle (WOT) cut-out relay is used to disengage the A/C compressor clutch during hard acceleration. This is accomplished by an ECM controlled relay.
The relay has a normally closed set of points. When energized, the points open to shut off the compressor clutch coil. The relay coil is supplied 12 volts by ignition and the ECM completes the circuit to ground to energize the relay when a high TPS voltage is input to the ECM.

Fig. 046 - Chart C-10B A/C Wide Open Throttle (WOT) Relay Check.:

1. Checks for normal A/C compressor operation at idle. Compressor should normally be "on".
2. Checks for A/C compressor cut-out at wide open throttle signal (full TPS). Compressor should normally go "off."
3. Checks for signal from ECM to energize A/C cut-out relay. If test light is "on," circuit up to the relay is complete and a good relay should energize. If test light is "off," fault is in ignition feed to relay or ECM wiring or ECM.
4. By jumpering relay connector terminals, the relay contact points are by-passed. This determines whether the problem is ECM/relay related or not. If the compressor remains "off," the fault is in A/C power flow. If compressor is "on" after jumping connector terminals, fault is ECM/relay related.
5. Determines if fault is in ECM or relay circuits. By connecting a test light across relay connector terminals, a false signal to energize the relay can be detected if the test light is "on." If the test light is "off," the fault is in relay connection or relay.