HMMWV in limp mode no trans light

[JPMcCormick1]

I have a 2003 M10445A2 that I have had for a year now and it has been in limp mode since I purchased it from the government. I have had several people look at it, replaced Transmission control module, protective control box, transmission relay, speed sensors and so forth. When I purchased it the Trans light indicator was missing so I purchased a new one. Whenever I start the vehicle the trans light does not come on. I even tried jumping the J2 A and E connector and no Trans light. I do get the TC control light come on when I put her in L or HL. It appears to me that the transmission control module is not getting power which could indicate why she is in limp mode. Today I decided to look at the battery connections and noticed something unusual. If you look at the first picture top left there is some wiring that goes to the relay box and then there are some cut wires off that same wiring that I did not first notice because they were hidden underneath the sheath. I dug them out and feel that this could be why the transmission control module is not getting any power. Does anyone know where these wires are suppose to go and why they might have been cut in the first place.

 

[86humv]

Here;s where they go...

 

[JPMcCormick1]

Here;s where they go...

Thank you. Worked like a charm. Humvee is out of limp mode, Trans light is now on and she cruises at 50 mph no problem and shifts gear automatically. Why would the government cut these wires. It was cut in such a fashion that it was almost like they were trying to hide the cut wires. The only reason I noticed it was because I noticed a bulge in the harness where the wires from the relay were coming from and thought that was weird. Once I peeled back the sheath I saw the cut wires. Is this part of the demil process?

 

[Coug]

not likely part of the demil process, more likely some jerk wanted to do it or thought he could use those wires somewhere else or on a different rig.

Glad to hear it's working for you now.

 

[JPMcCormick1]

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.

 

[Mogman]

This is what you needed to troubleshoot the power issue to the TCM, it is unfortunate you did not start with this before randomly swapping all those expensive parts.

 

[JPMcCormick1]

This is what you needed to troubleshoot the power issue to the TCM, it is unfortunate you did not start with this before randomly swapping all those expensive parts.

Thanks, that is a very useful document I had not seen it before.

Re the "swapping parts", I never did swap any parts I just reconnected all the wires that they had disconnected. Fortunately all the wires had the proper numbers on the silver tabs that made it easy to reconnect everything. I am still perplexed as to why it was disconnected. I tried checking for any blinking codes on the transmission light and there are none, so other then what was written in chalk on the actual transmission block it makes no sense why they would do that before putting her up on the auction block.

 

[Mullaney]

Thanks, that is a very useful document I had not seen it before.

Re the "swapping parts", I never did swap any parts I just reconnected all the wires that they had disconnected. Fortunately all the wires had the proper numbers on the silver tabs that made it easy to reconnect everything. I am still perplexed as to why it was disconnected. I tried checking for any blinking codes on the transmission light and there are none, so other then what was written in chalk on the actual transmission block it makes no sense why they would do that before putting her up on the auction block.

.
Funny how it works. I believe that sometimes the equipment would bring more money if "the stupids" didn't attack in the De-Mil process. Almost like if they possibly had a little training session it might benefit US and THEM. Of course then the purchase price would be more if the wires weren't pulled off the connectors. When it's really bad is if the wires are cut. Radio Trucks seem to be the worst for that...

 

[williamh]

Could have been there was something else connected to the 12v supply. Or they figured if they disabled the trans that they could get rid of it and got a new tactical vehicle. ??

 

[JPMcCormick1]

Could have been there was something else connected to the 12v supply. Or they figured if they disabled the trans that they could get rid of it and got a new tactical vehicle. ??

Interesting, I never thought about that strategy. The vehicle did have 17,000 miles on it which is one of the higher mileage Humvees I have bought from them as it is usually shows much less. I do realize you cannot really go on the odometer reading but nevertheless it was high.

 

[4x4nutz]

.
Funny how it works. I believe that sometimes the equipment would bring more money if "the stupids" didn't attack in the De-Mil process. Almost like if they possibly had a little training session it might benefit US and THEM. Of course then the purchase price would be more if the wires weren't pulled off the connectors. When it's really bad is if the wires are cut. Radio Trucks seem to be the worst for that...

Lol...the demil job only requires an IQ score 25 to 39 (Severe mental disability), and knowledge of sledge hammer, sawzall, pry bar, and cable cutters..

 

[DEA AK]

Here;s where they go...

Hi,
I could have the same issue... I had some wires cut.

When you stated "fat wire #290 to back battery +" did you mean...

a. that cable back to the battery (+) on the whole 24v system?
b. that cable back to the BACK (rear of truck) battery (+)

Thank you,
David

 

[JPMcCormick1]

Hi,
I could have the same issue... I had some wires cut.

When you stated "fat wire #290 to back battery +" did you mean...

a. that cable back to the battery (+) on the whole 24v system?
b. that cable back to the BACK (rear of truck) battery (+)

Thank you,
David

This is how I did mine. The fat wire goes to the plus on the back battery. By back battery we mean that you have two batteries under the seat one sits in front of the other. You want to connect to the + on the battery that sits towards the back of the seat as in the picture.

 

[DEA AK]

This is how I did mine. The fat wire goes to the plus on the back battery. By back battery we mean that you have two batteries under the seat one sits in front of the other. You want to connect to the + on the battery that sits towards the back of the seat as in the picture.

Thank you very much.

 

[4x4nutz]

Question is...if the speed sensor is not working, will it keep the trans light from coming on? The 1097 I am working on is getting power to the TCM, and I have jumped the A and E on the diagnostic port on the TCM. Still no tranny light at all.

 

[Mogman]

You should get a trans light when the run switch is put in run but the engine not running.
If you don't it is ether no power to the TCM, a bad trans light/wiring to the light or a bad TCM, that has nothing to do with any of the sensors.
There are two sources of power to the TCM one continuous and one switched, also check the grounds

 

[Mogman]

You need to find the reason you have no light before worrying about any sensors or trying to get codes.

 

[4x4nutz]

You need to find the reason you have no light before worrying about any sensors or trying to get codes.

Lol...thank you, but that's why I asked if a bad speed sensor would keep the trans light from going on. So your saying no, the light should still come on if the speed sensor if broken. I had checked everything else.

 

[4x4nutz]

Mogman...why don't you make the trip here to San Antonio

EDIT, you should not list your number on a forum, I will PM you. MM

 

[Mogman]

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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