ANY APU GURUS HERE

whats the controller say in red. stby, Alt. etc

 

i will tell you this about the alt. if the battery has a weak cell that the alt wires are hook too. the alt will time out and apu shuts down. it will throw a red alt sign on the main control knob. the alt has to sense a certain voltage to put out. you can switch wire to a different battery.

 

also see if apu will run with the truck key to the left. if truck has a failing ignition switch. it will cause apu to not come on

 

What is the alternator output?

 

If you have tri pak evolution you can plug into it and use software. USB cord bundled up by circuit controller under bed
If older style pre evolution no you can not read codes. Will have to go to dealer