Wires 2B and 2C on M1151

[Autonomy_Lost]

I've searched the TM for 2B and 2C but got zero results. I also searched this website and google, but found nothing.

I have 2 wires dangling under the hood, labeled 2B and 2C. One is male and one is female (I think?). They are part of the same wiring harness with no other wires, and they run through the firewall into the cab somewhere.

Does anyone know what these are for and where to hook them up?

Not sure if its related but my tachometer and temperature gauges are not functioning.

 

[Hummer Guy]

I've searched the TM for 2B and 2C but got zero results. I also searched this website and google, but found nothing.

I have 2 wires dangling under the hood, labeled 2B and 2C. One is male and one is female (I think?). They are part of the same wiring harness with no other wires, and they run through the firewall into the cab somewhere.

Does anyone know what these are for and where to hook them up?

Not sure if its related but my tachometer and temperature gauges are not functioning.

Someone correct me if I'm wrong, but I think those go to the generator. I can check today if no one gets here

 

[Autonomy_Lost]

Someone correct me if I'm wrong, but I think those go to the generator. I can check today if no one gets here

There is 2A that goes to the generator. But I dont have any open terminals on the generator at this point, and I dont have any charging issues that I know of.

 

[Hummer Guy]

There is 2A that goes to the generator. But I dont have any open terminals on the generator at this point, and I dont have any charging issues that I know of.

Seems like it have something to do with the heater

https://gear-report.com/wp-content/uploads/2017/03/TECHNICAL%20MANUAL%20UNIT%20MAINTENANCE%20for%20M998%20series.%20Part%203_HMMWV%20TM-9-2320-280-20-3%20Unit%20Maint%20Book%203.pdf

Page 12-148

 

[Autonomy_Lost]

Seems like it have something to do with the heater

https://gear-report.com/wp-content/uploads/2017/03/TECHNICAL%20MANUAL%20UNIT%20MAINTENANCE%20for%20M998%20series.%20Part%203_HMMWV%20TM-9-2320-280-20-3%20Unit%20Maint%20Book%203.pdf

Page 12-148

Interesting, thanks! I think that's probably something that was removed at some point. Pretty sure I don't have an arctic heater but I'll take a closer look tonight.

 

[Guyfang]

Seems like it have something to do with the heater

https://gear-report.com/wp-content/uploads/2017/03/TECHNICAL%20MANUAL%20UNIT%20MAINTENANCE%20for%20M998%20series.%20Part%203_HMMWV%20TM-9-2320-280-20-3%20Unit%20Maint%20Book%203.pdf

Page 12-148

Do you have a copy of the schematic?

 

[Hummer Guy]

Do you have a copy of the schematic?

Couldn't find it

 

[Mogman]

TM 9-2320-280-20-3 somewhere around page 1160. not sure if that is the TM for your vehicle but the number schemes are the same for all MVs with the exception of a few specialty accessories
Wire #2 is the alternator AC tap, used by the EESS and tachometer
The A,B,C,D etc are different branches or segments of the same circuit

 

[Mogman]

If they are male/female plug them together and see if the tach starts to work

 

[Autonomy_Lost]

TM 9-2320-280-20-3 somewhere around page 1160. not sure if that is the TM for your vehicle but the number schemes are the same for all MVs with the exception of a few specialty accessories
Wire #2 is the alternator AC tap, used by the EESS and tachometer
The A,B,C,D etc are different branches or segments of the same circuit

Wait a minute, here is the copy of that TM I'm looking at, which only goes up to page 953:

https://www.hmmwvinscale.com/ARMY%20TM%209-2320-280-20-2%20Technical%20Manual%20Unit%20Maintenance.pdf

And you're saying that A B and C can all just be spliced together?

 

[Mogman]

What I am saying is that the wire number is the circuit, in this example it is "AC tap" now on most earlier vehicles there is only a 2A, it goes from the AC tap terminal on the alternator to the EESS box and that is it'

On later versions that use the AC tap to feed the tach there could be a 2B, 2C, 2D, etc the A B C etc is ether different segments for example 97A and 97B go to the RPM sensor, different segments of the RPM circuit OR it could be branch circuits where the same circuit goes to multiple locations.

So some investigation needs to be done because nothing is absolute just like wire #2 being used in the arctic heater kit.

Pictures of the exact location would help

But because you have a tach and it is not working, if it is the type that uses the alt signal than that signal should be a #2 circuit, I have not been able to find the documentation on the tachs hopefully someone will step in here and help

 

[Autonomy_Lost]

I double checked, and 2C is actually a ring lug. 2B is a packard conector (male housing, female pin).

Conveniently, 2C will plug into 2A, and the ring lug can go on the AC output of the alternator regulator. I'm gonna try that and see what happens.

 

[Autonomy_Lost]

Tachometer works now!!!!

 

[Mogman]

Wait a minute, here is the copy of that TM I'm looking at, which only goes up to page 953:

https://www.hmmwvinscale.com/ARMY%20TM%209-2320-280-20-2%20Technical%20Manual%20Unit%20Maintenance.pdf

And you're saying that A B and C can all just be spliced together?

That is volume 2 you need volume 3

 

[Guyfang]

All well and good. But you still have no schematic. Having one and knowing how to read it is a good idea. What model truck do you have?

 

[Autonomy_Lost]

All well and good. But you still have no schematic. Having one and knowing how to read it is a good idea. What model truck do you have?

Its an M1151A1

 

[Guyfang]

That is volume 2 you need volume 3

Look at the cover of the TM, and see if that model is listed there.

 

[Mogman]

Look at the cover of the TM, and see if that model is listed there.

You are right that is an earlier TM. but What I had handy, sorry

 

[Autonomy_Lost]

Well at least I got my issue resolved, thanks everyone for the help!