Fuel pump relay/ fuse box

[dirtautoguy]

On my 96 k1500 Iv had a intermittent problem for a while. Yesterday it became not intermittent and I found the problem.

every once in a while my truck would start and die a second later for about a year.

To make a long story shorter I found that the female side of the fuel pump is a little messed up. One of the pins is pushed down so it can’t make very good contact. If I wiggle the relay while it’s running it will die

part of the plastic was broken as well. I was able to superglue the plastic back in place which helped but the pin is still loose and falls down.


So obviously that pin is the issue but what I need help with is what’s the best way to fix it? Get a new pin and replace it? Replace the whole fuse box? Bend the current pin so maybe it will fit tighter?

Last night I got the fuse box out but didn’t have enough time to figure out how to open it up to see the connections. For now I have a piece of cardboard shimming the relay so that it makes contact but obviously this is just a bandaid and could make it worse over time. Luckily we have a 3rd vehicle to drive for now but I’d like to get it fixed soon as I can. Thanks

 

[Erik the Awful]

I would try and repair or replace the terminal, but if the plastic's dorked, it might be a lost cause. Replacing the whole fuse block would be a major undertaking, and you'd have to be extremely careful about getting all the terminals in the right places on the new one. I don't envy your situation.

 

[Schurkey]

Why is your oil pressure switch not powering the fuel pump?

You should be able to remove the relay from a running engine, and the engine won't die because the fuel pump would be powered by the oil pressure switch. This may or may not work right at startup--the engine has to build oil pressure to trigger the switch. But a running engine with oil pressure should run when the fuel pump relay is removed.

First Guess on the fuse box: Broken/bent lock tab on the metal end of the wire. Remove that wire, inspect the terminal. Replace as needed.

If the fusebox itself is damaged, "good luck"; it'll be a nightmare to repair. I would consider pulling the wires for the fuel pump relay, and splicing them into a single-relay socket that you could locate somewhere near the fusebox. That, or stuffing the relay into the existing location, then making sure you have solid contact on the "iffy" wire by pushing it firmly onto the relay blade from below.

 

[dirtautoguy]

If I have to I’ll wire it to a separate relay and mount it somewhere.

Do you happen to know what kind of pins they are? I think I’ll pick some up if I can before I tear into it hopefully I’ll be able to fix it.

 

[dirtautoguy]

Ok so that brings up another issue. I though that it should shut off with no oil pressure too but last year when my oil cooler line blew apart it did not. Luckily I caught it before it drained all oil.

I do not believe the box is broken beyond use/repair. It was a this wall next the the pin that was broke, not off it was still hanging on. I was able to put it back in its place and glue it. It looks the way it should hopefully there isn’t more To that part

I plan on getting some extra pins just to be ready. Then I just gotta figure out how to get to the connections I can’t imagine it’s real complicated, and then hopefully I can repair the pin.

does anyone know what kind of pins they are or a pic so I have a better idea what would need to happen

 

[Schurkey]

Ok so that brings up another issue. I though that it should shut off with no oil pressure too but last year when my oil cooler line blew apart it did not. Luckily I caught it before it drained all oil.

Nope.

The oil pressure switch and the relay can turn the pump ON individually. BOTH have to be turned off to stop the pump.

Loss of oil pressure doesn't stop the pump, because the relay should still power the pump if the ECM is getting engine RPM signals.

I do not believe the box is broken beyond use/repair. It was a this wall next the the pin that was broke, not off it was still hanging on. I was able to put it back in its place and glue it. It looks the way it should hopefully there isn’t more To that part

I plan on getting some extra pins just to be ready. Then I just gotta figure out how to get to the connections I can’t imagine it’s real complicated, and then hopefully I can repair the pin.

does anyone know what kind of pins they are or a pic so I have a better idea what would need to happen

That'll be in the service manual.

Wouldn't surprise me to discover that they're Packard 56-style terminals.

Brass Female Lock Type Tab Connector 10 Pack

Automotive Electrical Repair Connectors and Tools

www.repairconnector.com

 

[dirtautoguy]

Ok so!!! It has been fixed! I got into it and it was worse than I thought. The bottom side had gotten quite toasty. It had partially melted and the wire insulation was peeling off. By the time I got the terminal out the plastic area around it was pretty bad and not usable

I took the pin to napa and got some replacements I’m not sure what the name for them are but they were the same. I cut back the burnt wire untill it had good clean wire and crimped a new terminal onto it. Then I moved the terminals to the relay holes labeled AIR my truck does not have that stuff on it so they were vacant.

there was another wire that didn’t look burnt but it did look a little worn or funny so I did the same to it and cut it back untill it was good solid wire.

All said and done the fuel pump seems to work perfect and the relay fits much better than it did. The only issue I have is that the square relay will not fit between the other relay and fuses. Atleast not with the cover on. So does anyone know if I can use a rectangular 5 pin relay that’s skinnier for the fuel pump?

 

[Schurkey]

I would expect that any relay of the appropriate voltage and amperage rating would be an adequate substitute--but I've never tried one.

 

[Erik the Awful]

Make sure the diagram and terminal locations on the new relay match the old relay. I discovered they're not all the same when diagnosing an inoperative circuit on our race car.