Trying to find the right TM to trouble shoot an electrical problem on a 5 ton

[C Big]

Can you help point me to the correct TM so I can trouble shoot an electrical problem on my M923. I have searched the treads and found a few comments about the electrical control box on the left side near the steering column, but have no idea how to trouble shoot.

What’s wrong you ask…. I had the alternator rebuilt because it would not charge. I put in two heavy duty industrial 12 volt batteries (which I will call Battery 1 and Battery 2)wired it for 24 volt. Truck starts and runs great. the next day battery 2 will be dead. By dead I mean DEAD will not take a charge and when tested the battery was ruined. The supplier replaced the battery for free and I put it in the truck. The truck started right up no problem. My hand held volt meter said 25 volts and i drove it around town for a few hours. When I got back to the house the truck would not restart when I tried. I found #2 battery dead again. I have taken the alternator back and had it test was told all is good. I can jump the truck with a 2 nd M923 and it starts just like it should.

 

[Artisan]

Perhaps you might navigate to TM 9-2320-272-24-1 then scroll sown to PDF page #266 and do the tasks described.

 

[MyothersanM1]

Perhaps you might navigate to TM 9-2320-272-24-1 then scroll sown to PDF page #266 and do the tasks described.

Same TM check Para. 2-22 starting on page 2-92. TM 9-2320-272-24-4 Appendix H has wiring schematics for more clarity.

 

[juanprado]

The newer 23 series tm's have great trouble shooting flow charts and steps.

http://www.jatonkam35s.com/jatonkaM939seriesTMdownloadpage.htm

 

[C Big]

A fellow SS Member has suggested by PM that the problem might be the 12v tap. Is it common for them to cause problems? And when they do turn evil what kind of problems does a bad 12v tap cause? (other than the obvious just not working)

 

[swbradley1]

Before reading your last post my thought was that it is the 12v tap. Something energized even with the truck off. Disconnect it and let the charged up batteries sit overnight.

 

[patracy]

Also consider installing the 939 series desktop application. Great diagrams for electrical there.

 

[Retiredwarhorses]

You should have a standard 60amp gen right...the charge output is adjustable....25volts seems low...heck, that may not be charging at all..Check the voltage when engine off then running..should be about 27.5 volts when running...what does the battery gauge read when running...?
the 60amp has a small Allen head you remove, small Phillips head down inside charging output up and down...takes 2 people....one in the truck with meter, the other making small adjustment.

2 batteries at 12.5 volts each is 25volts....

 

[C Big]

Ok so I started to take it all apart to try and find the problem. What I finally found was the battery cable to the #1 one battery was broken. (this is the one from the alternator to battery) Apparently it had been flexed too much in the past. I replaced that and so far I have had no problems. It does not explain all the problems I was having but I will keep an eye on it.
Thanks for the help.

 

[Hooper]

A fellow SS Member has suggested by PM that the problem might be the 12v tap. Is it common for them to cause problems? And when they do turn evil what kind of problems does a bad 12v tap cause? (other than the obvious just not working)

Cool< glad you found it, electrical problems are not fun.