Truck Starts, But Wont Run

[84WaterWagon]

I went on a road trip to NC to visit my brother (and to hit a few trails). On the way home my Wagon stopped running. I tried to start it and it runs as long as the key is in the "start" position, but as soon as it switches to the "run" circuit, I got nothing. The compression, spark, and gas is all working, no problems there. It's not the Ignition Module, but it's definitely something electrical. A few mechanics in the area looked at it for hours (they kept giving me that gruff look...)and they couldnt find the short (if there is one). I have a wire jumping the ignition coil right now, it works but its not right and I just dont like it. Has anyone ever had an experience similiar to this? Hey, does anyone know how to fix it? Thanx

[Jeepzilla]

According to the service manual, the problem is not a short but an open in the ignition circuit and it is probably the "resistance wire"--kinda like a ballast resistor. It is bypassed during "start" so that full battery voltage goes to the coil. In "run" the resistance wire carries all the juice. If that wire gets fried, no juice. Find the + terminal on the coil. Follow the red wire with tracer to a splice to another splice. The resistance wire is that segment between ths splices and is 1.35 ohm. Should be a standard replacement part...

[mrclean]

I'm not sure if that year has one, but a bad ballast resistor will cause the problem you describe. It will be on the firewall. Usually white, with two wires attached. When you locate it, use a jumper wire across the two wires and start the vehicle.

[JINGA]

Do you have accessories when in the "run" position? Do you have a wiring diagram?

Some times the ignition switch's contacts corrode or otherwise go bad over time. This would mean that even though the key is turned to the "run" position, the circuit is not being completed. All accessories and ignition would "die." (At least I think so!)

Check a wiring diagram to see what makes sense. I think both ignition and accessories run through the ignition switch. If your acc's died too, this might be it. Look for other places where a break or fault would cause both to die.

Since ignition switches are typically a PITA to change, I hope (for your sake) it's more mundane than this.

Of course, if your accessories didn't die, then look on the wiring diagram for someplace else. It's most likely a switch or contact point someplace. These tend to go more often than just a break in a wire.

If all else fails, do the super-sleuth one length of wire at a time chasing the voltage until you lose it.

HTH. Of course if actual mechanics worked on it for hours already, I'm sure they already looked in these directions.

JINGA

[shadowfax101]

could it be the ignition switch on the column? Just an idea. I had to change one out, not to bad...