So for a month my truck wouldn't start. And I just replaced my fuel pump relay and its now starting up. But I realized instantly the fuel pump relay is getting super hot to the touch. So I'm poking around and I see these two electrical connectors disconnected from something. It looks like they plug together but they dont fit. The yellow connector is coming out of the yellow plastic wire harness that I have the arrow pointing too. And the black connector is coming out of the main harness bundle that goes into the relay box, I got it pointing to the harness bundle.

So where do these connect? They look like they go together but they dont fit. I'm thinking maybe this is why the relay is getting ultra hot?

And why is the relay getting hot?

 

Your pump is probably going out, and that is cooking your relays.

I don't think the loose wires are related.

 

The pump is brand new!

 

OK if it's new then maybe there's a short in the wiring.

I think it's normal for a relay to be a bit warm, but not hot. So what would cause a relay to get hot ...
- It could have too high contact resistance, but you said it's new.
- It could passing too much current. (short in the pump or wiring). You can measure the pump current with a meter
- It's switching too frequently, which you would hear.

 

Alright mountainmanjoe I appreciate your help! So lets figure this out!

So how would I measure the pump current with a multi-meter? I got one. I dont use it all the time but I have used it before and understand some basics about it, how to check relays ect.

**update**

You Tube

Going to do this and I will let you know the results!

 

So I just went through and tested the current on the fuel pump just like in the video. And its pulling back 6 amps.

 

And then I went through this video.


This guy was fantastic. Really easy to follow. Everything pretty much happened exactly like his walk through. The only thing when I tested the control side of the circuit, my light only stays on for 2 seconds instead of 10. But everything else is working just like the video. Then went into the next video


And tested the oil pressure sensor, it turned on the fuel pump like the video. So I got a new oil pressure sensor unit coming, I'll pop that in tomorrow.

Aside from the new fuel pump relay getting ultra hot instantly when the truck is running, I know if I pull the relay, the truck will die and the back up unit in the oil pressure sensor does not take over. I always thought that was normal that pulling the relay kills the truck lol

Now on a second note of the relay getting ultra hot. My connection 30 is melted a little. This didn't just happen. If I remember correctly this has been like this for years in this truck. We had this problem "fixed" like 10 years ago. BUT I'm thinking, could the contact point not be tight enough and its causing the electricity to arc inside and heat this sucker up? But that would be weird because the truck has been running for 10 years with the connection point like that. So prob not that. Oh well. I'll put in the new oil pressure sensor unit and go from there

 

Yup that would fall under high contact resistance

 

What would?

And I just removed the relay box and looked under. The connector 30 wire is burnt and bare..... man..... those guys who "fixed" the truck, didnt fix the truck.

So how do I pop out the individual wires out of the back of the box?

 

Yeah I watched a bunch of videos on how to release wire terminals, I can see the empty ones and the little tab. But I still cant release any of the wired terminals. Not even the bad one. Whats the trick with these? Of course its not easy and straight forward.