To get my HMMWV (M1097A2) in good running order... need help.

[DEA AK]

I was told to only post a general 'help get my hmmwv running' kind of post so here I am. I guess by doing this I can post questions on various topics to get my truck to where it should be but I don't know.

Anyway, I have a 2004 M1097A2 and have a couple issues that I need help with at the moment.

1. Engine temp gauge - doesn't work.

2. Fan - on at start up and stays on (only had it running for about 15 mins total over a few days)

3. Rear right hand brake line - missing and can't even see where it actually goes for me to put in a new line (bought a metal brake line to install.

4. Coolant - if the coolant was all drained out at the yard for crushing, do all I need to do is fill it and run the engine to make sure coolant gets to wherever it needs to go?

5. Power steering - if atf was all drained out at the yard for crushing, do all I need to do is fill it and run the engine to make sure it gets to where it needs to go? I haven't driven it because I have not done the brakes BUT the power steering isn't working - I can't turn the wheel.

6. Heater control rods - don't push in or pull out, any ideas on how to get them free?

Thanks

 

[DREDnot]

First off...running the engine for any length of time with empty coolant and empty P/S fluid is BAD.

#1 wait till there is coolant in the engine first.

#2 Fan needs P/S system full to disengage. It operates in failsafe mode and turns on when something in the system fails or it shot up.

#3 That rear passenger brake line goes over the top of the caliper and goes in the upper front of the caliper







#4 Check that the drain petcock in the lower coolant hose/pipe is closed and check and replace any cut or old hoses before filling. I would recommend replacing the thermostat at this time as well because the coolant lubricates and prevents corrosion and an old dry thermostat may not open again. All easy stuff when the coolant is already drained. But to answer your question, yes if the system is intact just fill with 50/50 green coolant.

#5 Check for any disconnected/cut hoses from the draining. If its intact fill with ATF dexron II, III or VI depending on what you have available there. It runs the P/S system, The fan clutch system, The hydroboost Power brake system so follow all the lines to see where they disconnected something to drain it.
It will have a lot of air in the system and will be a whiney bitch thats a pain to bleed out.

You will have to have the brake line attached first or you will add more air to that system while trying to bleed the P/S and hit the brake pedal.

#6 spray them with PB blaster inside and out first thing and let them soak while you work on everything else. That may free them up.

 

[Mogman]

If you look at the left brake line you will see how the right side needs to be connected, according to the parts TM it takes a rubber and a steel line not just a steel line.
I think DREDnot has a basic or A1 truck.

 

[DREDnot]

I think DREDnot has a basic or A1 truck.

Thats my 1998(2009 rebuid) M1123

 

[Mogman]

I have to double down on what @DREDnot said, it is bad to EVER run an engine without coolant, or P/S fluid if the belts are on the engine, the water pump can be damaged in a very short time as the coolant is the lubricant for the water pump seal, same goes for the P/S pump, very bad juju to run without fluid.

 

[DEA AK]

I have to double down on what @DREDnot said, it is bad to EVER run an engine without coolant, or P/S fluid if the belts are on the engine, the water pump can be damaged in a very short time as the coolant is the lubricant for the water pump seal, same goes for the P/S pump, very bad juju to run without fluid.

Thx for the info.

Question - the yard said fluids were drained so I bought enough fluids for all systems including the coolant but after putting some in, I still have some left... Is there something I am to do to get the coolant to flow to all places it needs to go? I added it through the fill tank... maybe there was still some residual in the block after the yard drained it? All this is new to me - thank you.

 

[DREDnot]

Its very likely there is residual fluid in all the systems. Once all fluids are present start the truck with the radiator cap off and it will start to draw coolant into the system. Keep adding coolant to keep the tank at the full line so it doesn't gulp any air. When the thermostat opens you should feel the upper hose get hot. You should also start seeing hot coolant coming out of one of the two overflow hoses into the tank when its near full. Replace cap and make sure it builds pressure.

 

[DREDnot]

The P/S system will be whining at the same time so make sure you keep that reservoir topped up as well so it doesnt suck air.
Make sure there is ATF in the trans as well.

 

[DEA AK]

The P/S system will be whining at the same time so make sure you keep that reservoir topped up as well so it doesnt suck air.
Make sure there is ATF in the trans as well.

Thank you very much.

 

[DEA AK]

Its very likely there is residual fluid in all the systems. Once all fluids are present start the truck with the radiator cap off and it will start to draw coolant into the system. Keep adding coolant to keep the tank at the full line so it doesn't gulp any air. When the thermostat opens you should feel the upper hose get hot. You should also start seeing hot coolant coming out of one of the two overflow hoses into the tank when its near full. Replace cap and make sure it builds pressure.

Hi,
I took the coolant cap off, tank was filled with coolant, started the truck, let it run hoping to see it suck some coolant around through the engine. Didn't see it suck any from the tank but eventually started to see a little steam coming from the tank opening and the small hose closest to the windshield felt warm. Nothing from the big return hose... I squeezed it a bunch and it seemed as if that was causing some 'air' to be moved to the tank but that might have been just my imagination.

Either way, none of the coolant was sucked from the tank and the big hose never got hot or warm, from what I could tell.

Things could be okay but I am just worried that there is air in there or something and the coolant isn't flowing through the entire system.

Thank you,
David

 

[DEA AK]

tranny limp mode? Seems as if the truck is in limp mode. I don't get any transmission flashes and there were some smaller wires that were cut in the battery box but not connected to anything.

I have looked through the TMs and whatever I did find, I couldn't make heads or tails out of it and wasn't even sure if it was what I was looking for.

I believe that the TCM needs to be connected to the batteries somehow? Maybe through the smaller wires that were in the battery box?

If anyone has pictures that would clearly show how this is supposed to be so I could understand, I would appreciate it.

 

[Mogman]

tranny limp mode? Seems as if the truck is in limp mode. I don't get any transmission flashes and there were some smaller wires that were cut in the battery box but not connected to anything.

I have looked through the TMs and whatever I did find, I couldn't make heads or tails out of it and wasn't even sure if it was what I was looking for.

I believe that the TCM needs to be connected to the batteries somehow? Maybe through the smaller wires that were in the battery box?

If anyone has pictures that would clearly show how this is supposed to be so I could understand, I would appreciate it.

You should get a solid transmission light when the run switch is in the run position but not running, if not most likely the TCM has no power.

 

[DREDnot]

Coolant issue...If the engine has been running a while and you have steaming coolant at the reservoir but the top radiator hose is not getting hot(temp gauge working? past middle?) then your thermostat may be stuck closed. I would replace it with OEM as part of a complete servicing anyhow. Then verify that the hose gets hot when the new thermostat does open...that should allow air that may have been in the radiator to purge.

The trans issue... Rule number 1 in dealing with the trans computer...Any hooking up or unhooking of wires to/for the computer must only be performed with the rear battery negative cable and front battery positive cable disconnected to protect the TCM!!!

That said, on that panel behind the front passenger seat you should see a red push button. That is the reset for the TCM circuit breaker. Make sure to push that in. The TCM runs on 12 volts and the power supply wire for it should be attached to the rear battery Positive cable clamp. It usually has a yellow ring terminal connector. Verify that's in place. Open up the big green TCM box(under the drivers side rear seat) and make sure there is no water inside and that there is no indication there was or any corrosion evident. The box itself needs to be securely fastened to the floor and the contents need to be secure inside. I've seen to many of these trucks that have been "Rat Fucked" and these items scrounged and junk TCMs and housing boxes just loosely replaced.

Start there.

 

[DEA AK]

Coolant issue...If the engine has been running a while and you have steaming coolant at the reservoir but the top radiator hose is not getting hot(temp gauge working? past middle?) then your thermostat may be stuck closed. I would replace it with OEM as part of a complete servicing anyhow. Then verify that the hose gets hot when the new thermostat does open...that should allow air that may have been in the radiator to purge.

The trans issue... Rule number 1 in dealing with the trans computer...Any hooking up or unhooking of wires to/for the computer must only be performed with the rear battery negative cable and front battery positive cable disconnected to protect the TCM!!!

That said, on that panel behind the front passenger seat you should see a red push button. That is the reset for the TCM circuit breaker. Make sure to push that in. The TCM runs on 12 volts and the power supply wire for it should be attached to the rear battery Positive cable clamp. It usually has a yellow ring terminal connector. Verify that's in place. Open up the big green TCM box(under the drivers side rear seat) and make sure there is no water inside and that there is no indication there was or any corrosion evident. The box itself needs to be securely fastened to the floor and the contents need to be secure inside. I've seen to many of these trucks that have been "Rat Fucked" and these items scrounged and junk TCMs and housing boxes just loosely replaced.

Start there.

View attachment 906821

View attachment 906822

Hi,
I did put in a new thermostat (it was missing). With the engine running for a bit, the gauge does get up to about 160 and it stays there...

did you mean the red button is someplace near the batteries? I see the rope in both pictures but I don't remember seeing any red button. I see the round hole in the battery box picture, that must be where it is and that hole accesses it?

I do see the bigger black wire that comes from the top left of battery box that connects two small wires to the shunt and the bigger wire going to the (+) on the back battery, I have it but it's not connected. I'll connect that tonight (after I disconnect all battery wires).

Thanks so much for all the great info and very clear pictures!



View attachment 906823

 

[DREDnot]

The red reset button is behind the battery box under the B pillar cross brace. There is a space there that is protected from kicking by a plate at the front of the passenger rear footwell. You can remove that plate and see what all is in that space. Depending on your vehicle configuration there can be alot of electrical wiring, relays, and fuses and circuit breakers. That hole may access the reset button as mine is right behind that hole but you can see it from the top also (with the seat removed)

 

[DEA AK]

The red reset button is behind the battery box under the B pillar cross brace. There is a space there that is protected from kicking by a plate at the front of the passenger rear footwell. You can remove that plate and see what all is in that space. Depending on your vehicle configuration there can be alot of electrical wiring, relays, and fuses and circuit breakers. That hole may access the reset button as mine is right behind that hole but you can see it from the top also (with the seat removed)

Copy that, I found the red button, wired up the bigger wire to the battery and (knock on wood), the transmission is working! Now, I'll need to work on cleaning up the wires to remove corrosion. As well as proper bleeding of brakes and the cooling system.

Seems as if my power steering is getting better, I can feel it working (on / off / making noise) but the coolant doesn't seem to be moving through the system... or maybe it is and I just don't realize it???

 

[Mogman]

It takes a long time at idle (if ever) before you will feel any heat in that top hose, the small hose going to the reservoir getting warm is a good sign that water is moving in the system.
Just make sure the PS pump is full after every time you run it until the steering is working

 

[DEA AK]

It takes a long time at idle (if ever) before you will feel any heat in that top hose, the small hose going to the reservoir getting warm is a good sign that water is moving in the system.
Just make sure the PS pump is full after every time you run it until the steering is working

Copy, thank you.

 

[DEA AK]

The red reset button is behind the battery box under the B pillar cross brace. There is a space there that is protected from kicking by a plate at the front of the passenger rear footwell. You can remove that plate and see what all is in that space. Depending on your vehicle configuration there can be alot of electrical wiring, relays, and fuses and circuit breakers. That hole may access the reset button as mine is right behind that hole but you can see it from the top also (with the seat removed)

Took the truck for a spin. It seemed as if it was shifting just fine, drive it a bit, mostly slow on the back road and doing some turns. Then after heading back home, it seemed as if it didn’t want to shift so I went home and parked it.

The red button doesn’t really move at all when I press it.

Also, are you supposed fo press it when the truck is running or off or battery unplugged? I wasn’t able to locate info in the tm in it.

any help would be appreciated.

 

[Mogman]

Took the truck for a spin. It seemed as if it was shifting just fine, drive it a bit, mostly slow on the back road and doing some turns. Then after heading back home, it seemed as if it didn’t want to shift so I went home and parked it.

The red button doesn’t really move at all when I press it.

Also, are you supposed fo press it when the truck is running or off or battery unplugged? I wasn’t able to locate info in the tm in it.

any help would be appreciated.

First do you have a transmission light when in run position but not running? if not then you probably have a power issue, the red button an be pushed any time.
If you do have a transmission light as described above then you need to read the codes, all that information is in this guide.