Fuel pump relay wiring

[chuck_dungus]

So... I am a bit confused.

I've been having a fuel delivery problem and have narrowed it down to a loose fuel pump relay connection. My idea is to solder in a new fuel pump relay connector but I've run into a few issues.

First of all, it seems like the connector in there now has two wires going to the same pin. The new one I have (and all the other ones I've found online for sale) look slightly different.

Second, how do you remove the old connector and install the new one?
Also, I haven't been able to figure out of what each pin does from what I've searched on other threads. I need to make sure that I'm putting the right wires in the right spot, but since the old connector looks different I am confused how to do that. Can someone provide a diagram?

 

[ericbphoto]

Ok. This might get long. To begin with, the relay socket in your power distribution box is not removable. To use a new relay socket, you will be cutting the wires from the old and splicing them to the "pigtail" wires on your new socket. The new socket and relay will then need to be mounted somewhere nearby. The center wire (pink?) On your new socket will not be used.

Your original wires, that you cut away from the old socket, will be connected to the new socket as follows. Try to cut them as close to the plastic as possible so you have the maximum amount of wire to work with. My recommendation for making the splices is to make solder connections covered by heat shrink tubing. I'll link to a video about electrical connections below.

I'm including a picture of a standard relay, showing the internal wiring, terminal numbers and their arrangement on the bottom of the relay.

Here is the original wiring diagram from Ford.

Connect as follows;
Old black/yellow wire to red pigtail terminal 30
Old green/yellow wires (both) to yellow pigtail terminal 87
Old red wire to blue pigtail terminal 85
Old blue/orange wire to green pigtail terminal 86

Terminals 85 and 86 go to the coil in the relay. That is what closes the contacts and connects terminal 30 to terminal 87 to send power to the inertia switch and then the fuel pump. The other green/yellow wire from terminal 87 goes to the ECM to tell it that the relay contacts have closed and the fuel pump should have power.

I'll be back in a few minutes with some useful video links for you.

 

[ericbphoto]

How to make electrical connections

Troubleshooting your no start condition. (Just in case you have doubts about your analysis of the situation.)

 

[Uncle Gump]

You can also use a connector pick to release the lock tab on the faulty wire terminal in the junction block. Clean tighten that connection if possible and reinstall. Or just replace the terminal.

 

[ericbphoto]

You can also use a connector pick to release the lock tab on the faulty wire terminal in the junction block. Clean tighten that connection if possible and reinstall. Or just replace the terminal.

I have had trouble finding replacements for those terminals. I searched far and wide because I wanted to use the empty fuse and relay spots.

I have also found that once the connection becomes loose and the terminal starts heating up, it loses it's springiness and will meter hold tight again after you try to bend it back tighter. It will generally become a problem again and again...

Just my 2 cents.

 

[Uncle Gump]

I just put these in my Amazon cart... I'm refilling my electrical repair box. I've repaired a few over the years... if the junction box hasn't been over heated or busted up... I believe they will work.

Relay Connector, MUYI 5 Pin Relay Connector 12V Socket 30Amp 40Amp 6.3mm Truck Vehicle 5 Pack Car Relay https://a.co/d/0Gj3aHG

 

[Uncle Gump]

I am talking about just the terminals in this instance. The relay connector bodies will be good for new wiring opposed to using connectors with pigtails.

 

[ericbphoto]

I just put these in my Amazon cart... I'm refilling my electrical repair box. I've repaired a few over the years... if the junction box hasn't been over heated or busted up... I believe they will work.

Relay Connector, MUYI 5 Pin Relay Connector 12V Socket 30Amp 40Amp 6.3mm Truck Vehicle 5 Pack Car Relay https://a.co/d/0Gj3aHG

I like those. It's been a while. But I recall there are 2 different styles of connectors in the OEM fuse/relay box. I believe the one for pin 30, the sideways pin, is shaped different regarding the way it locks into the plastic. That is the one I could never find replacements for. I actually have several boxes from the junkyard that I wanted to custom wire. But could never overcome the odd terminal problem.

 

[chuck_dungus]

Ok. This might get long. To begin with, the relay socket in your power distribution box is not removable. To use a new relay socket, you will be cutting the wires from the old and splicing them to the "pigtail" wires on your new socket. The new socket and relay will then need to be mounted somewhere nearby. The center wire (pink?) On your new socket will not be used.

Your original wires, that you cut away from the old socket, will be connected to the new socket as follows. Try to cut them as close to the plastic as possible so you have the maximum amount of wire to work with. My recommendation for making the splices is to make solder connections covered by heat shrink tubing. I'll link to a video about electrical connections below.

I'm including a picture of a standard relay, showing the internal wiring, terminal numbers and their arrangement on the bottom of the relay.
View attachment 85183

View attachment 85184

Here is the original wiring diagram from Ford.
View attachment 85185

Connect as follows;
Old black/yellow wire to red pigtail terminal 30
Old green/yellow wires (both) to yellow pigtail terminal 87
Old red wire to blue pigtail terminal 85
Old blue/orange wire to green pigtail terminal 86

Terminals 85 and 86 go to the coil in the relay. That is what closes the contacts and connects terminal 30 to terminal 87 to send power to the inertia switch and then the fuel pump. The other green/yellow wire from terminal 87 goes to the ECM to tell it that the relay contacts have closed and the fuel pump should have power.

I'll be back in a few minutes with some useful video links for you.

Thanks, that was very helpful!

So, to reiterate what you said (because I want to make sure I do this right), I am going to cut the old fp relay wires from the box as close as I can to the pins and solder in the new connector I have as you described. I suppose I can pull out the center wire as it is not used. Then I will reroute the relay to somewhere outside the box.

Quick question before I do this. Why are there two wires going into pin 87? Do they go to different places? Lastly, will the one yellow wire on the new connector (pin 87) be able to carry enough amperage that both the yellow/green wires supply?

 

[ericbphoto]

Why are there two wires going into pin 87? Do they go to different places?

Yes. One goes to the inertia switch and the other goes to the computer. The pigtail wire should be large enough. The wire going to the computer really doesn't carry much current. It's just a signal wire telling the computer that the fuel pump relay contacts are closed.