APPLIES TO: This simplified ECM power and Ground circuits wiring diagram applies to the following vehicles:
F150:
- 4.9L L6 Ford F150 Pickup: 1987.
- 5.0L V8 Ford F150 Pickup: 1987.
F250:
- 4.9L L6 Ford F250 Pickup: 1987.
- 5.0L V8 Ford F250 Pickup: 1987.
F350:
- 4.9L L6 Ford F350 Pickup: 1987.
This wiring diagram includes the following circuits:
- EEC Power Relay.
- EEC Module Grounds.
EEC POWER RELAY TESTS: The ECM can't run without power —this tutorial shows how to test the EEC Power Relay step-by-step.
- Testing The Ford EEC Power Relay (Brown Relay).
- EEC Power Relay To PCM Circuit Tests (1985-1991 4.9L, 5.0L, 5.8L Ford F-Series Pickup).
WHERE TO BUY THE EEC POWER RELAY: Here are two EEC Power Relays from known brands I've used and trusted over the years —solid brands that have worked well for me in real-world repairs:
- Standard Motor Products RY-71T PCM Relay (Amazon affiliate link)
- Standard Motor Products RY71 Relay (Amazon affiliate link)
When you buy through these links, you help support the site and keep new wiring diagrams and step-by-step guides coming —and it doesn't cost you anything extra. Thank you!
EEC Power Relay Circuit Wiring Diagrams
- ECM Power And Ground Circuits Wiring Diagram (1985-1986 5.0L V8 Ford F-Series Pickup).
- ECM Power And Ground Circuits Wiring Diagram (1988 4.9L, 5.0L, 5.8L Ford F-Series Pickup).
- ECM Power And Ground Circuits Wiring Diagram (1989 4.9L, 5.0L, 5.8L Ford F-Series Pickup).
- ECM Power And Ground Circuits Wiring Diagram (1990-1991 4.9L, 5.0L, 5.8L Ford F-Series Pickup).
More Ford F-Series Pickup Tutorials
You can find a complete list of Ford F-Series pickup wiring diagrams and tutorials in this index:
Here's a sample of the tutorials you'll find in the index:
- How To Test The MAP Sensor (Ford F150, F250, F350).
- How To Test The Ford Fuel Pump Relay -No Start Troubleshooting (Green Relay).
- How To Test The Ford Ignition Control Module.
- How To Test The Ford Ignition Control Module (Distributor Mounted).
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