Question about APU

It is def an alternator code. It should be putting out 14ish while on, not 12,7. if your reading your dash volt meter thats prob what your truck has in the batts with apu off. if it doesnt go up a lot as soon as you turn it on alt is malfunctioning.

On mine, the alt was fine but the regulator wire fell off. There are 2 tiny white wires that lead to the alternator. if these are not connected, the tripack sences batts arnt charging and turns off after 2 min.

 

I am having a problem with my TriPac APU as well... When I am parked it works just find, most of the time but, sometimes it seems to wait too long before it fires up. The low voltage audible warning will come on in the truck and the APU will start to Initiate. It use to start before the Audible low voltage warning came on. Since it is starting later than usual, sometimes it will no fire up and give a low battery warning. If I reset, most times it will fire up on 2nd try but, yesterday (and today) I had to jump my batteries using my reefer because the APU wouldn't fire up at all.

Also, the APU has run while the truck is running, didn't used to. Used to shut off as soon as I turned the key to the on position.
Last think; When the APU is running and I turn the AC on or Heat, the APU shuts off. Than after a few minutes will fire back up. I am going to have ThermalKing look at it soon but, thought I would give TTR a try as well.

 

If the apu is running and you turn on the ac or heat, it will stop and restart. At least mine always does. The apu shouldn't run when the engine is running. There is a fused wire comming off the ignition switch that sends power to the apu control when the switch is in the on position to shut the apu off. If it is disconnected or the fuse blown then the apu will keep running. I was told by TK that it is not good to run both as it will possibly damage the alternators.

 

Have you changed the fuel filter?

 

I found the problem to mine..... My truck batteries were all toast! I thought they might be, for a while, so I got them checked. Now, I have 4 new ones and the APU is working like it is suppose to....thank God!