Smoking Ground Cable

[niferous]

Well I went to go move the M1009 tonight and it didn't want to start. The starter seemed to be dragging a little bit and I looked up and saw smoke rolling out of the hood around the batteries. I pop the hood and the battery cable that comes off the front negative post is smoking and the rubber has melted off and I can see exposed wire. I shut down the truck and disconnected the batteries just for good measure but not sure where to go from here. I'm not very experienced in automotive electrical issues so if someone could tell me what I need to check to diagnose this I would be greatly appreciative.

Edit to add: I forgot to mention the wire that burnt up was the small wire that comes off the terminal and goes towards the front of the truck. I'll try and snap a pic before I leave for work tomorrow. It was too dark tonight.

 

[steelandcanvas]

You have a loose connection. Clean everything up and put it all back together, making sure your connections are tight. If you did your PM's a little more often that wouldn't have happened.

 

[Blood_of_Tyrants]

Check the ground bolt to the engine block and the terminal crimps at both ends of the ground cable.

 

[6X6 ALL THE WAY]

sounds like its just grounding though the body ground

 

[Warthog]

Here is a list of the grounds I found in the wiring diagrams from the -34 manual. I'm sure it isn't all of them.

I would check the 2ga wire listed in the E-3 diagram and the Engine to Body wire in the E-1 diagram.

Grounds:
E-1 - Battery 1, Ground Strap, Waterinfuel,starter relay
E-3 - 2ga black from Neg Term Bk, combination sw
E-4 - Park Brake Sw, Fuel Tank Sender, Seat Belt Retractor, Bus Bar
E-9 - Bat1, Gen1 Ground, Gen2 Suppersor(most removed), Gen2 Relay
E-13 - Rt HL Body & Frame, LF HL Body, Volt&Heat Lt, #9 lead on cluster
E-14 - LF&Rt tail lt
E-18 - BO Hd Lt, BO tail lt
E-20 - horn, blower, horn button, wiper control, suppressors.

 

[Jones]

Like the earlier posts sez;
Replace both the large and small faulty grounds (the large ground isn't doing it's job for some reason and that's why the little one took all of the current) and clean all contact areas where they connect.
If you can find some of the combination inside/outside star washers the military uses, put one under the bolt head and one under the terminal end where the grounds attach to the block and body and/or frame.
If you can't find them, PM me; I've got enought to share.

 

[niferous]

Well I think I know the problem then. I disconnected my rear blackout lights a few weeks ago so I could start working on my back swing out tire carrier bumper. I didn't think anything of it and just left the wires hanging. I was mindful not to use my blackout lights though. Flash forward to Sunday and my little cousin is playing around in the CUCV and toggled those switches. Sound like a likely culprit?

 

[Barrman]

If your lights were off, there is no way for those wires to influence what happens at the batteries.

 

[steelandcanvas]

Niferous, As I said in my previous post, you had a loose connection. Most likely the Negative cable going to the frame. One of the few wires left to carry the circuit to ground was the small one you see burned up. Replace that, Check all your grounds. Re-install your battery cables and you should be fine.

 

[niferous]

The lights got turned on. I'll check the cable going to the frame. THANKS!

 

[niferous]

Well I checked all the connections and everything looked good. HOWever.... When I first started installing my AC kit I thought I needed to remove my wiring terminals right there behind the rear battery. I marked the top one but I think I may have mixed up the cables on the bottom one. I can't seem to find the diagram in the TM as to how all the cables hook up. If someone knows where to find it in there please let me know. However here is a picture. Let me know if this looks right.

 

[niferous]

Wow nobody knows how these hook up??

 

[Warthog]

Don't talk to me. I haven't had my morning coffee yet..................







There, I'm better. It's a wonderful day today...................


All the diagrams are in the -20 or -34 manuals. Appendix F or E. some of the wires are in multiple diagrams. I will list them all.

E-1 - pos term - wire 32 RED-1 - red 2 gauge wire going to starter
E-1 - pos term - wire 32 RED-1 - red 2 gauge wire going to pos term on rear battery
E-1 - pos term - wire 1 RED 22 - red 16 gauge fusable link going to starter relay under the dash
E-1 - neg term - wire 32 BLK-1 - black 2 gauge wire going to neg terminal of front battery

E-3 - neg term - wire 32 BLK-1 - black 2 gauge wire going to chassis ground

E-7 - pos term - wire 3 BLU 2a - blue 12 gauge fusable link going to the GP resistor pack
E-7 - neg term - wire .8 BLK 151 - black 18 gauge wire going to the GP module

E-9 - pos term - wire .5 ORN-2K - orange 20 gauge fusable link for GEN2
E-9 - pos term - wire 3 BLU-2L - blue 12 gauge fusable link for GEN2
E-9 - pos term - wire 32 RED-1 - red 2 gauge wire to pos term on rear battery (repeat)
E-9 - pos term - wire 32 RED-1 - red 2 gauge wire going to the slave receptacle
E-9 - neg term - wire 32 BLK-1 - black 2 gauge wire going to the neg term on the front battery (repeat)
E-9 - neg term - wire 32 BLK-1 - black 2 gauge wire going to the slave receptacle


E-11 - pos term - wire 1 RED-101A - red 8 gauge fusable link for the diagnostic system
E-11 - neg term - wire .8 BLK-150 - black 18 gauge wire for diagnostic

So to recap,

you will have 8 wires on the pos term - 3 large red, 2 small red, 2 blue and one orange.

5 wires on the neg - 3 large black and 2 small black


It only took me 30 minutes to open the files and color the lines............

 

[niferous]

Thanks!!! Looking at these diagrams it looks like everything is hooked up right then. I guess I could have a bad ground strap even if it's connected!

 

[Warthog]

Dont forget the Ground Strap in figure E-1. It connects the engine to the chassis. If I recall correctly, it is on the rear passenger intake manifold bolt and goes to the firewall.

Also you might remove the cables from the Neg Terminal Board and clean the copper strip that connects the lugs. They are usually corroded. Same for the positive Terminal board.

 

[mistaken1]

The lights got turned on. I'll check the cable going to the frame. THANKS!

If one of these wires were grounded when the lights were turned on then the fuse for these lights should have opened.

 

[niferous]

If one of these wires were grounded when the lights were turned on then the fuse for these lights should have opened.

Neither were grounded. They are both just hanging right now where the rear bumper used to be.

 

[niferous]

Ok I is an idiot and figured it out. I had the cable that goes from the engine ground over to the wire terminals DISCONNECTED. I was so embarrassed when I discovered it that I almost didn't want to say anything and just let the thread fade away but I'm hoping someone down the line might read it and learn something as I have.

 

[Warthog]

Glad you figured it out. Without that cable, all the juice was running thru that little ground wire at the front battery.

And thanks for completing the thread. I hate it when I am looking for the same issue and the threads have just died with no resolution.

Just for clarification, was it the ground strap in E-1 or the black wire in E-3?
Good job.

 

[niferous]

Neither actually. It was the cable that goes from the board to the engine manifold. Whichever one that is.

I also noticed my glow plugs don't seem to be cycling now. I may have fried something.