I have a 1979 F600 that a previous owner installed a Carter electric fuel pump on. Recently I replaced the brake booster and unknowingly mashed the hot wire to the fuel pump. I replaced the wire, then the relay started clicking. After I replaced the relay, when the key is off the pump is running. When I turn the key on the pump stops running. I put the old relay on and as long as I have the hot wire on the pump the pump is always running. I'll attach pictures in another post. Does anyone know what might be causing the pump to constantly run ? Thanks!!!

 

The first picture is the new relay, a 5 prong. The second picture is the old relay.

 

It sounds like the wire to the pump is on the NC (normally closed) terminal instead of the NO (normally open). Try switching the pump feed to the other relay terminal and see if it doesn’t work the way it’s supposed to.

 

My guess: Move the red wire on the center terminal (87) to the side (87a).

 

I think it’s the other way around. 87 would have power with the relay energized. He’s probably on 87a now.

 

If the pump runs with key off, then it's fed by the NC contact, 87a.

 

That’s what I said, and what I think you’re trying to say. He’s on the NC terminal now and needs to switch to NO (87).

 

Oh, right. I shouldn't post after wine.

 

Thanks for all the help, I moved the wire to 87 but got nothing to the pump with the key off or on. Is it possible I got a bad relay?

 

It's possible that you have your red wires reversed. I can't read the terminal numbers on your relay. Double-check that your four wires are connected as shown:




Hopefully your 30 line from unswitched 12v (ie battery) is fused! It's a common mistake to run an unfused line for accessories like this.

 

There is a circuit breaker on the wire supplying power to the relay and I have the wire to the pump on terminal 87. Could it be a problem with the actual wire going to the pump? Seems like the problem started when I repaired the wire after I mashed it on the brake booster

 

Do you have a multimeter? Check for voltage coming from the breaker. Or just pull the pump wire off the 87 terminal and flash it to the other red wire. The pump should run. If it doesn’t there either isn’t power from the relay or the relay doesn’t work.

If the pump runs when you flash the red wires together put the pump wire back on 87. Then use a jumper to flash from the red feed wire to the relay coil terminal that’s not grounded. The relay should click and the pump start. If it doesn’t then the relay is bad, you’re not getting a signal from the ignition circuit, or the red wires are swapped. For the latter you can check by using the same jumper and flashing from the other red wire to the ungrounded coil terminal.

And it never hurts to make sure you have a good clean ground at the pump and relay.

 

Correction-with this relay the only way I get power to the pump is if the wire is on 87a but only when the key is off. If I turn the key on, the pump does not run

 

Do you get power at 87 with the key on? If not it sounds like a bad relay. That, or you have the red wires crossed and aren’t feeding power to the C (common, “30”) terminal. The red wires should be as indicated in asavage’s photo above. The middle terminal isn’t used.

 

I have no power at 87. I'll get a new relay later this week and try it. Thanks guys!