APU quit working..need help.

We just serviced the Carrier APU a couple of weeks ago, and put on a new belt that was cracked. It was running rough along with the truck, so he put in a fuel additive. He took off the cover to hit the reset button, and now it won't fire up at all? Stumped as to what is going on with it. The truck is running better, but with no APU he is having to idle to keep warm. Does anyone have any suggestions that he can try?

 

Thanks, I will let him know, so that he can check those out.

 

Yeah that is what we were thinking, so he put in the fuel additive. The truck started running better, but that is when the APU quit. I'll tell him to look at the fuel filter, because it may have got clogged from the bad fuel.

 

Thanks MNdriver, I will let him know about that too. He said it won't even fire over, so that may be the problem too. He said that he will go out in the morning when he has light to look and see what is going on. I sure do appreciate everyone's suggestions, because this is his first APU and we just don't know enough about them.

 

Hmmm...that is what his was doing a few days ago, and now it won't fire over at all. He said the starter won't even come on. It is hard telling because that APU hadn't been serviced for quite some time, and it's possible that they might have damaged the wiring when putting the belt on. I will definitely let him know.