Electrical short causing brake lines turn red hot and starting fire

[JEEPCJTJ]

Hello Jeep Fans, I'm back and hunting Mr. Sparky.
Having been out of country for the past few months I was finally able to start the trouble shooting procedures as provided by G. Hayduke. Here's what I found and where I"m currently at in the troubleshooting process.

(A ton of information maybe confusing JEEPCJTJ)

Having done my best to highlight my troubleshooting process does anyone have any other recommendation for this new discover of the short to ground when I turn the ignition switch to the start position?

Thanks everyone for your help.

I want to get you some help here, even if it's not from me but either I'm not reading what posted correctly or you're not using the correct words.

Every short I've ever seen came with sparks. Shorts are bad and must NEVER happen because in short order they will cause a fire. (Short order, get it?) I also don't know what you have that makes a tone but if it's anything like a test light it's not finding a short.

I'm not saying that your alternator wasn't shorted, maybe it was but a voltage difference between any positive (even the positive side of the main fuse box) and any ground is how electricity works . Maybe the place you took the alternator to just wanted to make a sale, who knows?

Result of troubleshooting yesterday, 03-15-2020.
Back to turning the ignition switch from accessory to start I get a short from power plate of fuse box to ground, in this case my terminal clap is attached at the brake line. I can pull the 20 amp fuse from the fuse box and the short goes away, I have broken the circuit.
While looking for a possible bad wire I found I also get a short, or tone on my meter, when I pull my turn signal handle to the aft position as to turn on my bright lights. I can eliminate this tone by removing the 40 amp fuse that powers all the lights.

So, with both fuse installed in my fuse box I'm getting a short indication from my power plate of the fuse box to ground. I can disconnect the wire connector at the turn signal switch and ignition switch and identify the wire giving my the short tone. However, I have not been able to identify any place along the wire harness where the wires might be making direct contact with metal, the wire seem to be insulated.

Where do I go from here?

I think there is an "m" missing from the terminal clap. Misspelling terminal clamp ain't a big deal but I don't know what it is, why it's attached at the brake line or who put it there.

At this point I will say is that most of the "shorts" you've mentioned probably haven't caused those red hot brake lines.

 

[g.hayduke]

Result of troubleshooting yesterday, 03-15-2020.
Back to turning the ignition switch from accessory to start I get a short from power plate of fuse box to ground, in this case my terminal clap is attached at the brake line. I can pull the 20 amp fuse from the fuse box and the short goes away, I have broken the circuit.
While looking for a possible bad wire I found I also get a short, or tone on my meter, when I pull my turn signal handle to the aft position as to turn on my bright lights. I can eliminate this tone by removing the 40 amp fuse that powers all the lights.

So, with both fuse installed in my fuse box I'm getting a short indication from my power plate of the fuse box to ground. I can disconnect the wire connector at the turn signal switch and ignition switch and identify the wire giving my the short tone. However, I have not been able to identify any place along the wire harness where the wires might be making direct contact with metal, the wire seem to be insulated.

Where do I go from here?

I have to ask just to be sure. Are you trying to measure continuity on a live circuit? If not, please ignore and carry on.

Otherwise, I don't know what features your meter has but the few meters I have owned cannot measure continuity/resistance on a live circuit if you are trying to measure continuity between something that is actually hot and something that is actually grounded. In other words, you don't want to try and measure continuity on conductors through which current is flowing. I think if your meter is completing the circuit, it will probably beep. What does the display say while it's beeping?

 

[dbbd1]

Some DMM's have a diode check feature, which will beep at or near zero ohms.

Whether this is the case or not, we are all anxiously awaiting.

 

[ArmyMohawk269]

I'm using a Fluke77 meter and testing on a none powered circuit. I'm trying to figure out why going from the positive side of a fuse box, no battery cable attached, to a grounded point on the vehicle will cause my meter to show a completed circuit. If I get a tone on my meter it indicates there is a connection from my power side of the fuse box, metal tab area with two 10mm bolts, to ground. Should this type test set-up indicate an open circuit? Why do I get a tone when I select by dimmer switch on the column to high beams? Why do I get a tone when moving ignition switch to the start position?

So far, these are the only two circuits I have found to show a connection between the power side of the fuse box and ground. If I pull the fuses for these two circuits i show an open condition, no tone. "High beam and ignition switch"

I have not found any reason yet to be melting down my brake lines. The hunt continues and as always thanks for the suggestions.

 

[dbbd1]

Is something simple, like your headlight switch, on? You would have effectively zero ohms through the headlight fuse, switch and bulbs. (Just an example- your model year switches the ground for the headlights)

A drastic step would be to pull all of your fuses, in the PDC and inside. What happens now? Start putting one in at a time, what happens? At this juncture, put one in and take the previous one out. If you get 0 ohms on one circuit, note it and keep going, until you've done them all. Take a pic, or several, so you don't forget which fuse goes where.

 

[LONGJP2]

You will have continuity through devices and loads. Light bulbs, relays, etc. aren't open like switches.

The light switch and/or the key switch is what completes the circuit.

 

[ArmyMohawk269]

Took the leap of faith. Last weekend I took the leap of faith and applied power back to the Jeep and have not been able to duplicate the power to the break lines. Thanks for everyone's help during this trouble shooting process, but here's the results or what contributed though I'm still apprehensive of a hard fix.
1. Replaced all battery cables both positive and negative in the system. Good grounds!
2. At the time of melt down, noted alternator dropped to bottom of meter, zero. Tested alternator, failed testing therefore I replaced the alternator and belt. Save the old belt for emergency kit.
3. While removing the old battery I noticed one end of the battery was bulging. During the original event the battery and cables we really hot to the touch so maybe plates inside the battery melted as well. Though the battery was drained during the original discharge, the battery was not marked when installed and I bought this Jeep in 2017, therefore I replaced the battery with a higher CCA gel battery. (got rid of the lead acid)

Could the battery have shorted causing the alternator to fail and with the original battery cables installed, possible bad connection, allow the power to ground through brake lines?

I have taken the Jeep off road near my house, bounced it around in the wash-outs, drove it about ten miles around my house and have had no issue. Is the mystery solved, seem to be, hope it is?

Problems seems to be fixed, new cables, battery and alternator.

Thanks everyone for your guidance.

PS. Last weekend I bought a Gladiator so I now have a TJ & JT, funny how they have same letters. My plan is to start pulling my TJ to off-road places instead of driving it. I like the creature comforts of the newer model vehicle. But anyway, they are both Jeep's.

 

[ArmyMohawk269]

I just wanted to give and update on my repairs related to the shorted brake lines.
It is now May and I've driven the TJ a few hundred miles sense applying power back to the Jeep. At the current time everything seems to operate normal. I guess the battery and alternator were the issues with shorting through the brake lines. Don't forget, I also replaced all the negative grounding cables to larger sizes which might contribute to the fix. So far, all's well with the little TJ.

Thanks everyone for your help as I tried to find "Mr. Sparky".

Regards,