Main Cab Wiring Harness

[maxpearcy]

I am working on rebuilding the main cab wiring harness. I have all the wiring schematics and an old harness to look at. My harness is unfortunately in pretty rough shape and missing most of the bands. Does anyone have notes on wiring routings, lengths etc. Any additional information would be appreciated in helping sort out wire identification.

[greeno]

You’re looking for how they’re routed through the truck? When I rewired mine most everything was painfully obvious due to the lengths and where they had to go. Hardly had to use my pictures. Are you struggling with something specific.

[maxpearcy]

My harness that I am using for a pattern doesn't have any identification for each wire. I am trying to find out if anyone has drawn up a sketch or has notes on which wires are going in and out of the harness. For example about 16" down from the light control cannon plug about 4-5 wires exit the main wrap. One wire is still connected to the ignition switch so I am guessing it is #27. The other wires are ?? I am starting to dissect the harness now to find out but any notes would be appreciated.

[sturmtyger380]

I am in the process of running a new wiring harness in my cab. It's a Vintage Wiring of Maine harness I bought many years ago and has been stored in a box. Right now it's laying in the floor of the cab.

I can note the wire numbers and where they come off the harness. Might take a day or two.

[maxpearcy]

Thanks! I would appreciate that.

[sturmtyger380]

See if this makes sense:

Drivers Side Branch -
33 - Temp
16 - Dimmer SW
18A - Out from Dimmer SW
17B - Out from Dimmer SW
17C - Out from Dimmer SW
25A - Horn
25 - Circuit Breaker to Horn
12 - Ignition to Dist
36 - Oil Sender
491A- Marker Lamp
18B - Head Lamp
17C - Head Lamp
20A - Marker Lamp
19 - Blackout Head Lamp

Wires from Regulator - 4 - Goes to Starter, 10 goes to Circuit Breaker and 11 wires to main switch.

Cannon Plug
Near the Plug
40 - Panel Lights
25 - Horn
17 - Gauges Power
15 - Main Light Feed

Passenger Side Branch -
75A - Stop Switch
75 - Stop Switch Feed
21 - Service Tail Lamp
23 - Blackout Stop Lamp
22 - Service Stop Lamp
20B - Blackout Tail Lamp
20C - Marker Lamp
17A - Head Lamp
18 - Head Lamp
491B- Marker Lamp

[maxpearcy]

That is a huge help; thanks.

On the drivers side branch I see the wiring for oil and coolant (33 and 36); I am assuming these are the two connections to the senders. I would expect those wires to exit the harness somewhere around the cannon plug but I don't see them in your list. Where do they exit the harness or am I wrong in my initial assumption?

[sturmtyger380]

You are right. They have to run from the gauge back to the sending unit. I will look again. The sending units act like resistors and the gauge measures the flow of electricity compared to the 24v input.

[PoW]

Those connectors are Bendix series, not Cannon. Found in many MV's.

[maxpearcy]

Would you happen to know the correct Bendix part numbers for the connectors?

[sturmtyger380]

This was the connector I was referencing:

https://www.bigmikesmotorpool.com/colle ... or-7716895

[NAM VET]

where would we be if not for the support and advice of others on this forum. hal

[PoW]

The wiring loom splits a few inches from the lighting connector. There are wires for the ignition switch, gauges, dash lites, horn circuit breaker, and maybe something I've forgotten. It joins up with the front lighting looms under the dash area.

A look at the wiring diagram for your year (the early ones were simpler), best the one with turn signals will really help figuring it out.

One thing good about US tactical vehicles is many items are the same across many different ones. All use the same numeric code for individual wires, i.e. 91 is ground anywhere, any truck.

PoW

[sturmtyger380]

I went back and looked again. And yes there were some more wires I didn't record.

Cannon Plug -
Also Near the Plug but not in the other batch of wires near the plug:

12 - Ignition
36 - Out to Oil Sender (Plugs into gauge.)
33 - Out to Temp Sender (Plugs into gauge.)

Also, one wire comes from the rear harness and goes through the passenger side cowl front where the harness goes out on that side.
It's 28 from the rear Gas Sender (Plugs into gauge.)

Hope this helps you out. Alan

[maxpearcy]

I worked through the old harness I have over the weekend and came up with a schematic. I added the wiring for turn signals and an electric fuel pump. Feel free to let me know if you see any errors. I plan on starting to build it up this evening and would rather catch any problems before I start the wrap.