2009 Lmtv M1078A1 Charging System

[Ronmar]

here you go.... it is linked to in below thread. Quick search via google found it.

m1088... FMTV Wiring Diagram

Does any one know were I can get a Wiring Diagram for my M1088's A0 and A1 not having much luck looking in the TM Section. Thanks Chip

www.steelsoldiers.com

His is an A1R…

 

[Ronmar]

Dave did you find 24v on pin 30 of relay K11?

 

[Dave21]

A1 wiring diagram is in here somewhere; if Im not mistaken

Thanks I’ll keep looking.

 

[coachgeo]

Thanks I’ll keep looking.

ahhhh... sorry did not realize your's was an A1R.... the A1R schematic is NOT on here..... Just the A0 via TM's and the A1 a pull out from a TM somewhere.

 

[Dave21]

ahhhh... sorry did not realize your's was an A1R.... the A1R schematic is NOT on here..... Just the A0 via TM's and the A1 a pull out from a TM somewhere.

Thanks for looking.

 

[wheelspinner]

Thanks for looking.

Yeah I share your pain….

 

[AFman]

Just saw your post. I have a 2007 A1 that the no charge light just came on. I’m wondering how you resolved your problem and if so share that with me. Checking the voltage on the two leads going to the regulator I have 24 V on the AC terminal and 0 V on the exciter terminal the one closest to the pulley. I jumper 24 V to the exciter terminal and disconnected the wire to the AC terminal alternator putting out correct voltage. Reconnected the wire to the AC terminal Alternator Stop pudding out power. Changed out the polarity protection box no help. Appreciate any pointers she could give. Thanks

Me too! I just replaced all four batteries in my 2009 M1093a1. I was very happy because I managed to get the truck running after it had been sitting in my driveway for a year. I then noticed the "no charge" light came on. The two voltage gauges on the dash (the 24-volt and 12-volt) both remained in the yellow range around the 24 and 12 volt position respectively. I was very unhappy because my truck only has 5900 miles and not even broken in yet. I was about to take pictures and post them here for others to see when I realized that I have three wasp nests in my truck.

Anyway, I plan on reading other posts to see if a solution is already posted.

 

[Suprman]

Fold the cab see what color leds are flashing on the alternator regulator.

 

[Ronmar]

What superman said. No lights on the reg means either it isn’t getting excite power from K11 after the engine reaches 15 PSI oil pressure, or it has an issue. Green would be good, yellow low volt and red overvolt. I suspect they are either not lit or yellow otherwise the volt meter should be closer to 14/28V

That dash no charge light is actually driven by the LBCD which is located behind the cab…

 

[AFman]

Thank you all for your comments. I did as you suggested and raised the cab after starting the truck. I did not see any lights on the alternator while the truck was running. I took pictures of the gauges, the display panel showing the no charge light and the LBCD.

 

[Guruman]

Thank you all for your comments. I did as you suggested and raised the cab after starting the truck. I did not see any lights on the alternator while the truck was running. I took pictures of the gauges, the display panel showing the no charge light and the LBCD.

The dump body and van door lights would seem to be mutually exclusive, interesting. With that much weirdness, I'd suspect a chewed harness or a bad ground, but I don't have an A1 so I'm not much help. I hope you get it sorted.

 

[Ronmar]

No LED on the regulator means it isnt being told to come online(or broke). With the cab up and engine running, do you have 24v on the 24v alt output terminal?

if so you can use a jumper wire to apply 24v from the 24v terminal to the EXC screw terminal on the regulator. The exc terminal is the one forward/closest to the pulley. The leds should come on then. If they do not with 24 applied directly, the reg may be bad.

 

[wheelspinner]

Thank you all for your comments. I did as you suggested and raised the cab after starting the truck. I did not see any lights on the alternator while the truck was running. I took pictures of the gauges, the display panel showing the no charge light and the LBCD.

Ok ok.
pull your dash panel, unplug 912/913 I think are the numbers. They look like they should be together but they are for dump body and van body options. Cause ALL KINDS of gremlins when connected together.

 

[AFman]

Ok ok. pull your dash panel, unplug 912/913 I think are the numbers. They look like they should be together but they are for dump body and van body options. Cause ALL KINDS of gremlins when connected together.

I would be very disap

 

[AFman]

I would be very disap

Ok ok. pull your dash panel, unplug 912/913 I think are the numbers. They look like they should be together but they are for dump body and van body options. Cause ALL KINDS of gremlins when connected together.

I would be very disap

I would be very disap

What superman said. No lights on the reg means either it isn’t getting excite power from K11 after the engine reaches 15 PSI oil pressure, or it has an issue. Green would be good, yellow low volt and red overvolt. I suspect they are either not lit or yellow otherwise the volt meter should be closer to 14/28V That dash no charge light is actually driven by the LBCD which is located behind the cab…

Ok ok. pull your dash panel, unplug 912/913 I think are the numbers. They look like they should be together but they are for dump body and van body options. Cause ALL KINDS of gremlins when connected together.

Ok ok.
pull your dash panel, unplug 912/913 I think are the numbers. They look like they should be together but they are for dump body and van body options. Cause ALL KINDS of gremlins when connected together.

Ok. I pulled the dash panel, K11 and the Dump bed fuse. Everything looks new. Any ideas how I can test the relays and fuses to see if they are in good working order?

 

[wheelspinner]

Ok. I pulled the dash panel, K11 and the Dump bed fuse. Everything looks new. Any ideas how I can test the relays and fuses to see if they are in good working order?

No. Pull your gauge panel. Two large white plugs that look like they should be plugged into each other need to be unplugged. Those dump body and van alarms point right to that.

 

[Ronmar]

Yea the plugs he is referring to are under/behind the instrument panel. If you loosen the knob and raise/tilt the steering wheel as far up and back as it will go, you should be able to remove all the panel bolts and raise the top enough to access the wiring harness. You are looking for some plastic molded plugs, about 1” square. they will have aluminum label bands on them identifying them as 912 and 913.

If they are plugged together, separate them, set the panel back in place, apply power and see if the dump lights are still lit. If they are cleared, start the truck and see if the charging fail light clears and if your voltages return to a proper 14.1 and 28.2V.

 

[AFman]

Thanks. I will do that this weekend,

 

[wheelspinner]

Thanks. I will do that this weekend,

How did you make out?