Circuit Test B - EEC-V Power Relay

WARNING: This page is about a different car, the 1995 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.

This circuit test is only intended to diagnose the following components and circuits:

Vehicle wiring harness circuits (VPWR, IGNITION START/RUN, B+ and Ground).
EEC-V power relay.
Constant Control Relay Module (CCRM).
Powertrain Control Module (PCM).

Fig 1: EEC-V Power Relay Test Circuits (Ranger)

1) Check VPWR Circuit Continuity

Turn ignition off. Disconnect Idle Air Control (IAC) solenoid and EEC-V power relay wiring harness connectors. Disconnect scan tool (if applicable). Measure resistance between VPWR terminal of IAC solenoid connector and VPWR terminal of EEC-V power relay. If resistance is less than 5 ohms, reconnect IAC solenoid and go to next step. If resistance is 5 ohms or more, repair open in VPWR circuit between EEC-V power relay and IAC solenoid.

2) Check Ground Circuit To EEC-V Power Relay

Leave ignition off and EEC-V power relay disconnected. Measure resistance between ground terminal of EEC-V power relay and negative battery terminal. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in ground circuit.

3) Check Voltage To EEC-V Power Relay

Leave ignition off and EEC-V power relay disconnected. Connect DVOM negative lead to negative battery terminal. Measure voltage at B+ terminal of EEC-V power relay connector. Turn ignition on. Measure voltage at IGN START/RUN. If voltage is less than 10.5 volts, repair open circuit and repeat QUICK TEST. If voltage is more than 10.5 volts, replace EEC-V power relay and repeat QUICK TEST.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 5). No test procedures have been omitted.

5) Check Ground Circuit From CCRM

Leave ignition off and EEC-V power relay disconnected. Disconnect CCRM. Measure resistance between pin No. 15 (Black wire) of CCRM wiring harness connector and negative terminal of battery. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in circuit and repeat QUICK TEST.

6) Check Ground Circuit Between EEC-V Power Relay & CCRM -Leave ignition off. Measure resistance between pin No. 9 (Yellow wire) of CCRM wiring harness connector and ground circuit of EEC-V power relay connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in circuit and repeat QUICK TEST.

7) Check Ground Circuit In CCRM

Leave ignition off. Connect ohmmeter negative lead to pin No. 15 of CCRM. Connect positive lead to terminal No. 9 of CCRM. Measure resistance. If resistance is less than 5 ohms, ground circuit is okay and testing is complete. If resistance is 5 ohms or more, verify that circuit is not shorted to power. If circuit is okay, replace CCRM and repeat QUICK TEST.