HMMWV in limp mode no trans light

[4x4nutz]

All you should need is power to the TCM and a connected and working light, the transmission could be unplugged for all the TCM would care at that point.
It would be handy if you had an LED test light like this one, it shows green for "correct" polarity but more important it also lights up red for reverse polarity.
You want an LED light for this test so you would not overload the TCM MIL light circuit.
you simply connect the clip to positive 12V, turn on the run switch, then see if it lights up red when the probe is connected pin U (wire 657A) at the TCM J1
This eliminates the wiring to the MIL light and the MIL light itself.

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Thank you Mogman! Got both the 1097 and the 1151 shifting like champs in no time at all!!! Your a master Humveesman!

 

[Mogman]

Thank you Mogman! Got both the 1097 and the 1151 shifting like champs in no time at all!!! Your a master Humveesman!

Your welcome, it was nice meeting you, I am glad I could help!
Nice collection of truck!!

 

[Mstng65HummrMan]

I just purchased another HMMWV (M1151A1) and to my surprise this one was also in limp mode just like the one I posted here back in 2020. My initial thought was, here we go again, some more cut wires. To my surprise there were no cut wires just a lot of disconnected wires in the fuse area behind the battery compartment. Just about all the wires controlling the transmission were unplugged. As soon as I plugged them all back in she ran fine, no limp mode.

My question is that being the second Humvee I have purchased from the government that had a transmission disabled I am trying to figure out why they would do this. There are some letters written in chalk on the transmission case that I am not sure what they mean. On one side it is written "dea" on the other side "code A" and then "150T248 or 2y8" not sure if that before last letter is a y or number 4. Does anyone know if these codes written on the transmission mean anything. She is running absolutely fine so not sure why they would disconnect the transmission wires unless they thought there was a problem.

I KNOW THIS IS OLD, but can you please post some pics of the M1151A1s bus wiring behind the front seat? Some of my wires were disconnected at the innermost bus screw, three red wires just hanging loose next to the stud. Are they part of the AC system I hope because mine inset turning on with the dash switch…

Thanks!

 

[Mogman]

I KNOW THIS IS OLD, but can you please post some pics of the M1151A1s bus wiring behind the front seat? Some of my wires were disconnected at the innermost bus screw, three red wires just hanging loose next to the stud. Are they part of the AC system I hope because mine inset turning on with the dash switch…

Thanks!

Do you have the schematics?
If not what is your serial number?

 

[mrfarb]

Not sure how much this will help.

 

[williamh]

The trans is run off the 12v system.

 

[Mogman]

The trans is run off the 12v system.

He has not confirmed that he has a schematic which of course would be the first step.