HMMWV won't start, transmission light is on

[scbean]

We drove our 2001 M1123 HMMWV into the middle of nowhere on federal land and when we went to leave it won't turn over.

Getting there, no issues, every previous time has never had an issue with starting. The batteries are 12.7 and 12.75 so I do not think it is the batteries.

At first, turning the start box to run the wait light turned on solid for a few seconds and then turned off, as expected. Then when we went to "Start" it made some mild sounds (similar to how a car sounds with a VERY dead battery) and since then the only light that will turn on consistently (in any state, eng stop, run or start) is the transmission light in the "run" state.

We suspect a cable / wire was vibrated out of place since we have been driving it off road a fair amount since we got it. We tried tightening all the battery connections and there was no change.

Any ideas?

 

[Thunderbirds]

We drove our 2001 M1123 HMMWV into the middle of nowhere on federal land and when we went to leave it won't turn over.

Getting there, no issues, every previous time has never had an issue with starting. The batteries are 12.7 and 12.75 so I do not think it is the batteries.

At first, turning the start box to run the wait light turned on solid for a few seconds and then turned off, as expected. Then when we went to "Start" it made some mild sounds (similar to how a car sounds with a VERY dead battery) and since then the only light that will turn on consistently (in any state, eng stop, run or start) is the transmission light in the "run" state.

We suspect a cable / wire was vibrated out of place since we have been driving it off road a fair amount since we got it. We tried tightening all the battery connections and there was no change.

Any ideas?

.

Check all the major ground cables, AND the starter cable and ground. Make sure you wiggle any cables or tighten lugs ONLY with the ignition off. A sudden reconnection may fry components and most likely will create arcs and sparks...

The trans light should stay on if the engine is not running until it is started.

Good luck! Keep us updated.

 

[NDT]

Check ground stud on shunt where it passes through the body.

 

[scbean]

Checked all the grounds, everything looks good. Could it be the ignition switch?

 

[scbean]

The ignition switch is fine and getting 24V, just double checked. The trans light comes on but the break light and wait light do not. The wait light does not seem to get any power checked by a multimeter. They use to light up for a split second when first turned to run, but not anymore. You can hear what sounds like a relay just behind the battery compartment switching when you go from stop to run. The heater blower also doesn't have power, it use to run when you were in "run" mode.
Also none of the dash indicators do anything when in the run position. Anything people can think of?

 

[williamh]

Same issue I am having. Haven’t found the issue as of yet.

 

[Gcelevator]

The ignition switch is fine and getting 24V, just double checked. The trans light comes on but the break light and wait light do not. The wait light does not seem to get any power checked by a multimeter. They use to light up for a split second when first turned to run, but not anymore. You can hear what sounds like a relay just behind the battery compartment switching when you go from stop to run. The heater blower also doesn't have power, it use to run when you were in
Also none of the dash indicators do anything when in the run position. Anything people can think of?

Hey there. Did you check your park switch (it is a 4 speed i guess) are you getting power to the starter selenoid? Probably your smart box went kaboom and is not allowing the power to ho through. Try also jumping out on the diagnostic port and see if it starts.

 

[scbean]

Hey there. Did you check your park switch (it is a 4 speed i guess) are you getting power to the starter selenoid? Probably your smart box went kaboom and is not allowing the power to ho through. Try also jumping out on the diagnostic port and see if it starts.

It seems like it is likely the start box, I am strongly considering getting a CAMO one since this seems like a VERY common issue with the S3 box, unless someone has a different suggestion. I spoke with the owner of CAMPO for a bit and replacing the box and possibly the glow plugs seems like the next move...

 

[TOBASH]

It seems like it is likely the start box, I am strongly considering getting a CAMO one since this seems like a VERY common issue with the S3 box, unless someone has a different suggestion. I spoke with the owner of CAMPO for a bit and replacing the box and possibly the glow plugs seems like the next move...

Read my sig line for DIY PCB/EESS box instructions.

Lots of happy rebuilders.

 

[Milcommoguy]

It seems like it is likely the start box, I am strongly considering getting a CAMO one since this seems like a VERY common issue with the S3 box, unless someone has a different suggestion. I spoke with the owner of CAMPO for a bit and replacing the box and possibly the glow plugs seems like the next move...

Good talking with you on your start / glow issues. Sure, you can build one or buy one.

Just like a HUMMWV, CAMO

 

[86humv]

camo box....best out there.

 

[tomelroy]

load test the batteries first.