Help truck shut off on highway

[Ozymandias]

Back in these days they often used the same parts for all vehicles, that's the reason for this.
For example, car was sold with manual mirrors. But the entire wiring is already in the car.

Today that isn't

 

[GAmes]

More than likely there are other things powered by that relay. The horn fuse is also connected to the AC circuit in mine.

 

[jpogue]

The relay tested fine so I tested the other one next to it for the ABS pump and it was working as well.

 

[jpogue]

So replaced ignition switch and harness truck fired right up. Took for a test drive made it about 3 miles truck shutdown again. Check fuse 9 it’s blown. Replace fuse get 200 yards down the road it blows again. Replace fuse again don’t make it 20 ft blown again. Replace fuse start and once it starts I can hear it blow. I had a box of cheap fuses so I have my wife come get me. We go get a decent fuse and same thing I start and it blows. So once again facing humiliation of being towed home again. WTF!

 

[Ozymandias]

I see Fuel pump, AC compressor, ASD relay and something else hanging on this fuse.

AC is easy to rule out, disconnect it.
What's next?

.......

I'm using this kind of fuses > https://www.ebay.com/i/123419338259...31123&itm=123419338259&pmt=1&noa=1&pg=2386202

Come in very handy for such problems.

 

[jpogue]

Oh man I didn't know that there were resettable fuses. So even though the relay tested fine I replaced it and the truck fired up. I'm leary on driving it anywhere I live on a steep hill and no way could my wife's car tow it up. Since it ran fine for a few miles then a few hundred yards and then 20 feet I'm going to let it idle for a while tomorrow and drive up and down the driveway for a bit and see what happens. Tonight though I'll go through some wiring diagrams again. So from the looks of the diagram and simple under the hood observation and in simple terms, it seems to me that the power goes from the battery to the power distribution center where the relays are and then the relay sends that power through the fuse block to the items the fuse protects. Is that right? Thank you for your help

 

[fest3er]

Could be heat-related, like a wire that stretches when it gets hot and has worn through the insulation. Look for a chafed wire, or a wire that has inexplicable 'scorch' marks on it, wire that's close enough to grounded metal to raise suspicions. If the engine dies instantly (like it was shut off), I might start with the wiring for the fuel shutoff solenoid.

The resettable fuse for my power seat was hot enough to burn my finger in a few tens of milliseconds, to flash spittle to steam. Started digging around the seat, took the bottom cushion off and finally found where a wire was shorting against the seat frame. Plenty of scorch marks on the wire and the frame.

 

[jpogue]

Yes I'm definitely going to have to do some detective work and wire tracing. Thanks fest3er

 

[jpogue]

Well it wasn't the relay after all. Fired up the truck and let it idle and after 10 minutes or so fuse 9 blew again. I'm calling dodge today to see just exactly what the tech did when he was doing his "diagnosis."

 

[DavidC]

Relay's very rarely ever go bad, Solenoids yes. The main thing on relays are arced contacts but that will not cause fuses to blow, now solenoids can heat up, draw a lot of amps or simply a shorted coil.

 

[Ozymandias]

Did you disconnect the ac compressor?

That would be next.

 

[Ozymandias]

Could be heat-related, like a wire that stretches when it gets hot and has worn through the insulation. Look for a chafed wire, or a wire that has inexplicable 'scorch' marks on it, wire that's close enough to grounded metal to raise suspicions. If the engine dies instantly (like it was shut off), I might start with the wiring for the fuel shutoff solenoid.

The resettable fuse for my power seat was hot enough to burn my finger in a few tens of milliseconds, to flash spittle to steam. Started digging around the seat, took the bottom cushion off and finally found where a wire was shorting against the seat frame. Plenty of scorch marks on the wire and the frame.

That's a different kind of fuse, self-resetting, the power windows are made the same.
The ones I mentioned you need to push the button back in, they dont get hot because they are swift fuses.

 

[DavidC]

Can the fuel shutoff solenoid be disconnected and pinned to the run condition ?. Then run to verify.

 

[BigPapa]

Can the fuel shutoff solenoid be disconnected and pinned to the run condition ?. Then run to verify.

Yes, just unhook it, pull the lever up and tie it off or remove the pin and pull the lever up. Just need to realize the lever will have to be turned down to shut the truck off. The relay run off fuse #9 is for the "hold up" side of the solenoid. The "pull up" relay is on the firewall and is powered from fuse #2 in the PDC when the starter is engaged.

 

[mwilson]

I've been wondering if it might be the "Run" side of the shut off solenoid....I see I'm not alone....

 

[jpogue]

Thank you guys I had a meeting this morning, and have been on phone with insurance company about tow bill from yesterday. Shouldn't have been a bill only 5 miles from the house and I have tow coverage. I will disconnect the AC compressor and as BigPapa noted I will push rod up on shutoff solenoid probably just remove the clip on the end of the rod if I'm not mistaken that should do it. I've had shutoff solenoid issues before and replaced. Dodge still has not called me back. I hate letting other people touch my truck

 

[DavidC]

I've been wondering if it might be the "Run" side of the shut off solenoid....I see I'm not alone....

Yeah, it's not a direct short according to what I have read, something is heating up and the fuel shutoff is probably the most used component. Worth a try.

 

[GAmes]

Don't take the clip off. It is what moves the shut off lever on the pump.

 

[jpogue]

Okay going to zip tie the shutoff solenoid up first and disconnect the plug for the solenoid and start and let run to see what happens. First off it's lunchtime for me and the kid. Will post results in an hour or so. Thanks guys

 

[jpogue]

Okay unplugged shutoff solenoid and zip tied up. Running 10 minutes so far and no shut off tach still working