Wire Routing Question...Tracking wires after a harness massacre

[dhaumann69166]

Hi everyone I am new to the HMMWV community and need your help! I recently purchased a ‘93 AM General M1038. The previous owner cut the main wiring harness coming into the cab in front of your right knee and removed all the headlight wiring in the cab. When he cut it he only left a couple inches of wire on the inside and none of them have the steel tags. I have managed to track down most of the headlight and front lighting wires but I am having trouble figuring out which ones control tail lights and brake. Also there are a few wires that I don’t know what they go to. I have searched all over and looked at tons of wiring diagrams but I haven’t found anything that shows wire routing and what all wires are in that harness. Any help would be greatly appreciated. Have a happy new year.

 

[bikeman]

The -20 TM should have a wiring diagram, but in all honesty, I'd just try to find a replacement harness.


I think the additional wires you are finding are for the blackout system. If all these have been cut, to include the connector to the light switch (which also includes dash lighting) you're going to be fighting a lot of wires.

 

[doghead]

Please do not start multiple threads on the same subject.

 

[dhaumann69166]

Literally the whole wiring harness has been cut and most wires gone. How much does a wiring harness go for? What company would you recommend looking at for a new one? I would like to be able to just re wire it myself to save money but if a new harness is cheap I would go that route. Do any of the TM’s show wire routing or what wires are in each harness?

 

[ikoinu]

I agree with bikeman on the replacing the entire harness rather than patching together. You will lose durability and waterproof-ness. I bought a secondary glow plug harness from epay and ran it to make a manual controller rather than splicing. Sorry you have to deal with that, I wonder what the existing issues were that caused the former owner to Vorhees the harness?

 

[dhaumann69166]

Didnt mean to start two. Sorry. Not the greatest with internet lol

 

[ikoinu]

Ouch! Just looked on a popular online auction site... They had one listed for a M998/A1: $939 obo

 

[bikeman]

I'd check with Eastern Surplus or a few of the other places that sell HMMWV parts... but, as much as I choke at the thought of $1,000 harness, it doesn't really surprise me. Supply and demand...

 

[ikoinu]

Eriksmilitarysupply has it for $260

 

[aleigh]

If you do want to make a run at tracing the old wires, I find a tone wand to be helpful for this problem. Disconnect the battery first.

 

[Action]

If you do want to make a run at tracing the old wires, I find a tone wand to be helpful for this problem. Disconnect the battery first.

x2. The free multi meters at Harbor Freight have a tone continuity setting. Put one wire in the dim headlight plug. Touch all the wires under the dash. When it beeps, mark that wire with the same number that is by the light. Do this for every wire. The diagrams are in the very back of the last TM. The part book will show what hooks to each plug.

 

[aleigh]

The tone generators I use are a little box which plugs into one end of the wire and a "wand" that you can wave over the wire. It works through the insulation based on proximity. So you can hookup at the dash then go in the engine bay. It'll beep louder as you get closer to the wire. They are common in the networking world when you are trying to trace low voltage wiring through the walls.

Where it breaks down is if the wire goes to ground or the routing is complex (like one wire energizes a bunch of wires) but I still find it saves time.

 

[dhaumann69166]

A new harness is WAY out of my budget unfortunately! Going to have to keep tracking down wires. I am using heat shrink on all connections to keep them waterproof. Going to have to redo all the s#!tty connections the previous owner did. I have been putting 12v to each pin on connectors one at a time then probing with a test light. Tone meter sounds MUCH easier but the nearest parts/tool store is about 80 miles. As of this afternoon I have over half the wires tracked down and labeled. I have headlights, front markers and rear markers, front BO drive light, dash lights, brake light on dash, and heater. Also figured out why they chopped it. Ground wire to the windshield wiper switch melted from the switch to the ground bolt. Didn’t seem to do much damage so I still don’t know why they felt the need to cut so much out.
When I put power to wire 21 (tail lights), wire 22/460/461 (brake lights), wire 23 (BO Stop), and wire 24 (BO tail) and probe the wiring harness 4 wires light up in the cab. Since the same 4 wires light up at the same time how do I tell what wire I connect to what terminal on my light switch?

 

[86humv]

A new harness is WAY out of my budget unfortunately! Going to have to keep tracking down wires. I am using heat shrink on all connections to keep them waterproof. Going to have to redo all the s#!tty connections the previous owner did. I have been putting 12v to each pin on connectors one at a time then probing with a test light. Tone meter sounds MUCH easier but the nearest parts/tool store is about 80 miles. As of this afternoon I have over half the wires tracked down and labeled. I have headlights, front markers and rear markers, front BO drive light, dash lights, brake light on dash, and heater. Also figured out why they chopped it. Ground wire to the windshield wiper switch melted from the switch to the ground bolt. Didn’t seem to do much damage so I still don’t know why they felt the need to cut so much out.
When I put power to wire 21 (tail lights), wire 22/460/461 (brake lights), wire 23 (BO Stop), and wire 24 (BO tail) and probe the wiring harness 4 wires light up in the cab. Since the same 4 wires light up at the same time how do I tell what wire I connect to what terminal on my light switch?

I have a new body harness for $ 450 plus ship...
The $ 260 one at Eriks is a eng. harness
Eriks body harness is $ 685

 

[aleigh]

For your consideration; https://www.rbracing-rsr.com/wiring_ecu.html

Although if you do it that well maybe the replacement cost will look competitive. Interesting info though especially about water ingress. The struggle is real.

 

[papakb]

If your not familiar with using a tone wand for wire tracing here's a link to a you tube video on how to use one. These things used to be called a fox and hound but the principle is the same. This is much easier than trying to chase wires with a multimeter. Harbor Freight has one for about $25.

https://www.youtube.com/watch?v=9gTA5kuL8YA

 

[StackJ]

I don't want you to get ripped off and you seem to be in need. PM me. I have a wiring harness that would be way less - you just need to figure out a way to remove it. I might be able to find someone. I don't have time.

 

[dhaumann69166]

Thanks for the offers on the harness but for now I am going to repair what I have. If I start replacing wires I will have to replace everything. I need the engine harness, body harness, turn signal and headlights.... the only thing that hasn’t been cut into is the hood wiring harness. I have everything found except tail lights and brake. Might have them figured out but waiting on new bulbs to get here. Nobody with 120 miles carries 24v parts. Hopefully tomorrow when the headlights and tail light bulbs get here I will have lights. Then on to building a turn signal harness.

 

[m109a2]

Welcome dhaumann69166 from Lake Charles La.My wife is from Fall City Nebraska.That being said lets start the ball rolling(1)Same gauge wire with oil resident insulation Stranded never solid on DC voltage.(2)Shink tubing,Brady wire peel and stick markers,a meter with continuity, A soldering gun, solder not acid core,and alligator clip for rear light trouble shooting.Now lets go to work.splice averting Cut your wires log enough to hit every device on the vehicle and the switch separate each wire and label to the tm or your own but please label.2 inches of wire to spice does blow give me a call Al {337)-477-1067

 

[donquijote]

Welcome dhaumann69166 from Lake Charles La.My wife is from Fall City Nebraska.That being said lets start the ball rolling(1)Same gauge wire with oil resident insulation Stranded never solid on DC voltage.(2)Shink tubing,Brady wire peel and stick markers,a meter with continuity, A soldering gun, solder not acid core,and alligator clip for rear light trouble shooting.Now lets go to work.splice averting Cut your wires log enough to hit every device on the vehicle and the switch separate each wire and label to the tm or your own but please label.2 inches of wire to spice does blow give me a call Al {337)-477-1067

Wow another person from lake Charles here... wouldn't have guessed that! Figured I was the only one

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