Bad end to a great weekend!

[MTboatguy]

Well my wife and I went camping in our new to us 5th wheel, great weekend, but on the way home, ended up with a short in the truck due to **** poor install of an after market oil gauge, the pressure tube shorted out on the firewall and blew the capillary tube apart, spewed oil all over the place and caused a fire. Got the fire out, but now the truck won't turn off with the key, I had to pull the power to the injection solenoid, when I did that the truck quit, but the glow plug light stays on, I was wondering, if someone could point me in the right direction and what electrical system to look at?

 

[rbh]

Re: Bad end to a great weekend!

MTBG, that sucks bud!
What a crappy way to end the weekend.
For the wiring issue I think with the fire you melted your key hot wire to a constant hot wire, your going to have to do some searching and taping up burnt wires or use a jumper from the battery for your glow plug relay till you find the culprit.

 

[rbh]

Re: Bad end to a great weekend!

Did you find the burnt wires?

 

[MTboatguy]

Re: Bad end to a great weekend!

Did you find the burnt wires?

Not yet, the only burnt wire I have found so far, is a ground lead that is attached to a stud on the wiper motor, but I know there is a fused wire in there somewhere, because even without the ignition switch in it, which I am going to replace, I still have power at the injection solenoid and the glow plug light, this is going to be a nightmare, for a simple engine this thing has miles of wire in it! I have the dash out of it and no burnt wires behind the dash, I am starting to suspect the burnt wire is on the glow plug circuit, as the glow plug light is the only circuit with power inside the cab when the batteries are hooked up and the injector solenoid has power with the batteries hooked up.

 

[MTboatguy]

Re: Bad end to a great weekend!

Well RBH, I did find something out that is interesting, I definitely have a short, if I hook my test light up to the negative side of the battery and touch any bare metal on the truck, I get a glowing light!, so the whole truck is charged at this point in time when I hook the battery up!

 

[rbh]

Re: Bad end to a great weekend!

YIKES!
It going to be a burnt wire to ground or a chaffed wire to ground.
I bet a beer that the issue is right where the oil tube went through the fire wall, when they drilled the hole they nicked a main power feed and that's how your tube shorted out and melted in the first place.

BTW, check to see if the electric trailer brake controller wires are not rubbed through??? (rubber grommet in place?)

 

[Tim Frank]

Re: Bad end to a great weekend!

Well RBH, I did find something out that is interesting, I definitely have a short, if I hook my test light up to the negative side of the battery and touch any bare metal on the truck, I get a glowing light!, so the whole truck is charged at this point in time when I hook the battery up!

Try sequentially pulling fuses to see if you can isolate/identify the problem circuit(s).

 

[rbh]

Re: Bad end to a great weekend!

Try sequentially pulling fuses to see if you can isolate/identify the problem circuit(s).

Morning Tim-
I was thinking the same thing, but would a fuse in a circuit dead shorted to the chassis not pop?

 

[bruceb58]

Re: Bad end to a great weekend!

Its not a short circuit to ground. That's why the fuse doesn't blow.

I would do the fuse pull too. If that doesn't turn off the test light, there is a rogue wire that someone installed that you will need to find.

 

[rbh]

Re: Bad end to a great weekend!

Its not a short circuit to ground. That's why the fuse doesn't blow.

I would do the fuse pull too. If that doesn't turn off the test light, there is a rogue wire that someone installed that you will need to find.

Bruce, going off of post #5, the chassis is energized when the battery leads are hooked up.
And if this was a fused circuit, would it not pop the fuse?

 

[NYBo]

Re: Bad end to a great weekend!

Well RBH, I did find something out that is interesting, I definitely have a short, if I hook my test light up to the negative side of the battery and touch any bare metal on the truck, I get a glowing light!, so the whole truck is charged at this point in time when I hook the battery up!

This means you have a break in the cable(s) from the negative battery terminal to chassis ground. There is no other way for this to occur. Of course, you may have other issues too. Run another ground wire and see which, if any, fuse pops. It's likely you are seeing normal current from various things in the electrical system with the test light completing the circuit to ground. However, be prepared to yank the ground wire free in case something that's not fused is amiss.

 

[Fleetwin]

Re: Bad end to a great weekend!

Morning Tim-
I was thinking the same thing, but would a fuse in a circuit dead shorted to the chassis not pop?

What kind of vehicle are you looking at?

 

[bruceb58]

Re: Bad end to a great weekend!

Bruce, going off of post #5, the chassis is energized when the battery leads are hooked up.
And if this was a fused circuit, would it not pop the fuse?

That just means his test light is completing a circuit that is turned on. For example, if you had your doors open(interior lights would normally go on) and you put your test light between the battery negative terminal and the frame, the light will go on because it is completing the circuit.

His test light is going on because a circuit is connected when it shouldn't be. Of course we are making an assumption that he isn't doing his test with the doors open or a hood light on!

 

[bruceb58]

Re: Bad end to a great weekend!

This means you have a break in the cable(s) from the negative battery terminal to chassis ground.

I was assuming from his test that he had the negative battery terminal removed already.

 

[MTboatguy]

Re: Bad end to a great weekend!

This is a 1985 6.9 diesel, there is no power in the cab, the ignition switch is disconnected. I have pulled all of the fuses and circuit breakers out and there is still power at the glow plug light as well as the fuel injector solenoid, so I am presuming direct short completing a circuit. When this happened Sunday, I could not turn the truck off with key, once I got it turned off, I had no power except to the GP light and the fuel injector solenoid.

 

[bruceb58]

Re: Bad end to a great weekend!

Is there a wire loom at the firewall that suffered fire damage? If so, some insulation probably melted off multiple wires allowing a constant 12V wire, possibly one that sources the fuse box, to now be connected to your glow plug circuit.

 

[NYBo]

Re: Bad end to a great weekend!

I was assuming from his test that he had the negative battery terminal removed already.

:facepalm: Of course! This is what I get for only glancing at one part of a thread.:redface:

Is there a wire loom at the firewall that suffered fire damage? If so, some insulation probably melted off multiple wires allowing a constant 12V wire, possibly one that sources the fuse box, to now be connected to your glow plug circuit.

This is a very plausible explanation. Also check for bad relays. I'm pretty sure the glow plugs, at least, are powered by one. Also remember some circuits may be protected by fusible links rather than fuses or circuit breakers.

 

[MTboatguy]

Re: Bad end to a great weekend!

Well after more trouble shooting this evening, I found a weird thing, when connecting and disconnecting the ground with the hot side of the battery hooked up, I get a small but higher pitched staticy type sound in the condenser fins in front of the radiator on the passenger side, there was only one hot wire running close to the cooling condenser was the factory brake controller hot wire, which I have completely pulled out and disconnected. So it is definitely a hot wire that is fused somewhere, I will be darned if I can find it. Does anyone know of a good quality short circuit tester that actually works?

Yes, the glow plugs are run through a glow plug relay and there are fuse links all over the engine compartment in this truck, but have check all of them that I can find, none seem swelled up as if blown.

 

[Tim Frank]

Re: Bad end to a great weekend!

If you won't do the sequential fuse pulling thing....go the other way and pull them ALL.
Then put them BACK one at a time ...watching your test lamp.
If you find a circuit that lights the lamp, take note, pull that fuse again, and keep going. You can expect two or more circuits to be a problem.

 

[MTboatguy]

Re: Bad end to a great weekend!

If you won't do the sequential fuse pulling thing....go the other way and pull them ALL.
Then put them BACK one at a time ...watching your test lamp.
If you find a circuit that lights the lamp, take note, pull that fuse again, and keep going. You can expect two or more circuits to be a problem.

Tim,

I already pulled all of them when this all started and still had power to the two circuits I mentioned. I will be checking draw again after I get off work tomorrow. My biggest problem, is all of the information I am finding pertains to gas vehicles, this one is a diesel and nobody seems to have any information for trouble shooting them, I keep getting "Take it to the shop" Which is not feasible, as the closest diesel shop to me is over 125 miles away, not an easy or cheap task with a vehicle that does not run!