54 Pin Plug wire diagram needed

[tager705]

Hi everyone,

I am in the process of fixing shorts, random hacked wires etc. I had basically ignored this cap until i bumped it and the cover popped off to revealed I think a 54 pin plug. I asked all my friends that used to drive the HMMWV and got the following suggestions which don't seem to make sense.

option 1:Slave port.
Option 2: radio plug
Option 3: diagnostic computer plug.

I'm inclined to believe its option 2 but from my research most of the radios run on a 9 Pin connector, also a vote against this option is on the passenger side I have a large black cable that's been chopped off (De-milled). Clearly its not a slave port two pins vs 54 pin. Option three is kind of out because I don't think their is an ECU on the HMMWV so how would it have a diagnostic plug.

Here is a photo of the plug, mostly just curiosity as to its purpose and if any one has a wiring diagram. Thanks

 

[NDT]

The crude "STE-ICE" (simplified test equipment internal combustion engine) plugs in there. Totally analog inputs to the device such as fuel pressure, cranking amps etc. It does not need to be connected.

 

[Stonepicker1]

Item #6

 

[tager705]

Sweet thanks.
I had only seen the OBD style diagnostic tool plugs. Sounds like I get to go buy a new tool.

 

[snowtrac nome]

have fun finding one in all my years in the motor pool I used it once for training. the plug can be handy as plug s and t goes straight to the starter solenoid and if you have a control box failure with a paper clip you can start the truck from that plug

 

[DREAD KT]

Wow! Never heard of starting the starter solenoid if there is a control box failure with a paper clip you can start the truck from that plug. Can anyone provide details? I just ran into this problem and it would save me a trip with the tow truck! Thanks!

 

[Mogman]

Wow! Never heard of starting the starter solenoid if there is a control box failure with a paper clip you can start the truck from that plug. Can anyone provide details? I just ran into this problem and it would save me a trip with the tow truck! Thanks!

If you short S and T on the STE plug you will activate the starter IF it is working and has power.
That does not mean it is going to start, you still need power to the IP.
If everyone that owns a HMMWV had downloaded and READ the free TMs available on this site it would have saved many folks thousands of dollars.

 

[DREAD KT]

Many thanks! Yes, I have all the TM's for this any my other vehicles, but do not recall seeing this. Will take another look. Struggling with a bad harness (I think). Starter is not getting a signal from 74A and everything else checks out.

 

[Mogman]

Many thanks! Yes, I have all the TM's for this any my other vehicles, but do not recall seeing this. Will take another look. Struggling with a bad harness (I think). Starter is not getting a signal from 74A and everything else checks out.

Try S and T that plug has independent wires to the positive post on the starter (T) and to the solenoid (S)
If that does not work check T to ground with a volt meter, if you do not have 24V there then the starter is likely not getting any power.

 

[86humv]

74a power goes through the nuetral safety sw., the to start box....then to starter

 

[DREAD KT]

Thanks again. Been going through the checks in TM-9-2320-280-20. So far, I have good switches (rotary and neutral switches), power to the starter (6A), and continuity at 14 (A&B). What I do not have is a signal at 74A to the starter. Need to check continuity at body harness today to see if I don't have a harness problem or a bad control box. I honestly think my starter is good but will find out later today.

Also trying to fix a leaky drain plug on my M274A5 at the same time. Will get to the wheel gaskets on the M109A4 later!

 

[Mogman]

74a power goes through the nuetral safety sw., the to start box....then to starter

If shorting S and T gets the truck cranking then as[B] 86humv[/B] said start tracing the 74A circuit until you find the problem, if shorting S and T does not work then you have a problem with the starter and or power to the starter.