60amp 24v no to little charge

[ross165123]

I have an m818 with a 24v 60amp alternator with a no charge issue. The truck with star and run all day long but the battery charge will be at 24.7v all day long, I tried to adjust the voltage regulator but no change. So when looking at TM 9-2320-260-20 on page 2-115 test 3 it says to check the input voltage and if non replace alternator. the was no voltage at the wire but wouldn't that mean there problem is upstream for the alternator?

 

[m38inmaine]

There is a 24v sense wire going to the alternator, if I remember correctly you should see battery voltage at that wire with the ignition on. If you have voltage at the wire with the switch on and have cranked the adjust screw all the way up then I would say the alternator is bad.

 

[jpg]

Before you declare it bad, it's worth disassembling, cleaning, and using contact grease on all the connections. You could simply have corrosion in a connection. If this is the problem, a new alt won't help. I've also replaced battery cables that had corrosion under the insulator, to the point where only a few strands were carrying current.

I use a stainless steel wire brush and/or fine abrasive mesh to clean the copper contacts until they're bright. Then I use no-ox-ide dielectric grease to kill any remaining oxide, and prevent its return.

I'd try the cheap fixes first. Even if you eventually replace the alt, the new one will have good connections.

 

[ross165123]

the sense wire has no voltage with the ignition on. and according to the tm it says to replace the alternator witch does not sound right?

 

[ross165123]

Could a bad battery switch cause this? I looked further back to lead 459 from the battery switch and there is no power to it.

 

[m38inmaine]

If no voltage at the wire you need to trace it back, I'm not familiar with your wiring but you need to find the source of 24 volts to this wire. It is possible that the switch is bad. To test the alternator you could use a test lead and connect the 24+ at the alternator and the sense wire at the alternator and see if it produces voltage.

 

[74M35A2]

As a quick test you could jumper +24v to the alt terminals that is supposed to have it, taken right from the alternator B+ connection. I'll be selling mine soon if you decide to replace it with a stock one.

 

[Monkeyboyarmy]

I'm thinking that power might go through the pcb box.

 

[gimpyrobb]

Make sure you have charged your batterys individually first. If they are low, there might not be enough juice to "turn on"the alt.

That being said, it sounds like you have an "open" somewhere upstream of your alt. I believe MBA is on the right path, do you have a spare pcb to try?

 

[ross165123]

I do not have a spare pcb. I did us a jumper to send a signal to the alternator and it worked at 26v so went ahead and adjusted it to 28.2v so I know my battery switch is bad for sure so I will replace that and if it dosent work then I will look for a pcb.