M1151A1 A/C Wiring Harness Replacement

[HoveringHMMWV]

Last November I purchased a GovPlanet M1151A1 that had the inside wiring harness cut during the demil process. Challenges right off hand were to confirm what had been cut, what I had and what was needed. I was able to locate a new harness via one of the trusted vendors and am starting the replacement procedure. An initial hurdle was to determine the purpose of a bundle of three cut wires coming out from the side of the upper passenger footwell area. Using a wiring diagram, cut wire tags from behind the front passenger seat, and input from other SS forum members, I was able to discern that they were for the heated windshield that had also been removed during demil. Removing/Installing the rear portion of the harness was straightforward. Rear evaporator to forward harness, to CB's, to battery box ground shunt and power post went smoothly. My most difficult hurdle is now how to pass the harness through the passenger footwell sidewall and into the engine compartment. I am wanting to limit the amount of work involved but to also have a neat and tidy repair. After wavering, I ultimately decided to forego removing the front evaporator/heater to aid in creating space for the repair. Instead, I'm opting for creating a set of "jumper" wires that will pass through the original sidewall grommet. Once the wires are through the grommet, I will solder and crimp the appropriate mil-type connector for each end. I made work space by removing the snorkel, air filter can and hoses, draining the coolant system, removing the surge tank and associated hoses, and finally heater hoses along with the shutoff solenoid. The extra space gained allowed me to tag or note wire pairs before disconnecting. Snipping off the disconnected wires then allowed me to pull the old harness wiring thru the grommet and into the footwell. More updates to follow as the heat and humidity have ended my work for the day.

Very little work space between the footwell sidewall grommet and a/c evaporator.


Removing components in order to access wiring harness behind and below surge tank.


Removing the heater hoses allowed access to the wiring harness identification tags.


After snipping off the wires, I was able to pull the harness into the footwell.

 

[HoveringHMMWV]

Made up my jumper wires today complete with new packard connectors and using tags from the old set.
Thanks to @wadeyoung for the extra set of hands in helping feed the wires through the firewall grommet. Still need to trim off the excess and create the appropriate connectors on the inside.

 

[HoveringHMMWV]

Was able to finish up the wiring inside before the heat got unbearable. All of the wires are connected and tucked away behind the evap console. Found enough space up high behind the crossover duct. If I was to do it again, I would have shortened the wires by another 6" or so but I didn't want to end up too short. I even added new silicone to the power post studs. Tomorrow morning I'm planning on reconnecting the surge tank along with new associated hoses, new heater hoses and solenoid valve, air filter can and hose, and finally the batteries. Fingers crossed.
FYI.... Found a few more 5.56 Lake City cases inside the dash ducting. That's a total of three 50 cal cases and links and about fifteen 5.56 cases and links found on and within the vehicle.

 

[HoveringHMMWV]

Finished reconnecting everything up this morning. Very fortunate that there were no drips or seeps from the coolant system. The a/c worked as advertised with the exception that the compressor cycled on/off every 3-4 seconds. Feeling good about the repair as there were no flashes, arcs, bangs, or smoke emanating from any component. Now to get the R-134a refrigerant serviced.

 

[someone]

Hey i know it's been 2.5 years but I'm wondering if you remember where you got the wiring harness. I have the same wires also cut.

 

[HoveringHMMWV]

I ordered the harness from MacMotors. Always great to work with.

 

[charger #1047]

Hello I also need a/c wire harness Do you have part # to order Mac Motors Thanks mike

 

[HoveringHMMWV]

Not sure what vehicles y'all have but the wiring harnesses can be found in TM 9-2320-387-24P (and can be found on the SS website).
I have an M1151A1 and the harnesses begin with "Fig 274B A/C System Circuit Breakers".
For my vehicle, I needed....

- Mac Motors

and

- Mac Motors

But prices have increased SIGNIFICANTLY! I would not consider building my own harness for those prices.
HTH.

 

[someone]

Thank you. I newer to reading the TM but I eventually found it.