No power to fuel pump

JOLINBERG

MEMBER
1987 FORD BRONCO
98,000 MILES

It was running well when I was driving then it just quit. I had it towed home and realized the relay was not opening so I bought a new relay. Still nothing. Plug to relay has 4 connectors relay had 5? 3 plugs had power one at 12.5v one at 5.4v and the last at 1.46v with the ignition off. The relay still doesnt open. I have no power at all to fuel pump when key turned so it doesnt even prime. I have changed the ground wire from neg post on battery to frame. And I have cleaned and tested ground strap from back of motor to the firewall.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

This sounds like a possible control issue, but we need to find out if the module is grounding the relay.

The way to do this is to put your red meter lead on the battery positive and then the other on the relay terminal coming from the module.

Then turn the key on. The meter should read 12 volts. If it does, then the module is fine.

Here are a couple of guides that will help with this:

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

I attached the wiring diagrams below which will help with this as well.

Please run through this and let us know what questions you have.

Thanks

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