APU expert?

You might have gotten some water and degreaser where it ought not be......wiring, ecm....connector...etc. take connectors apart and let them air out. Then add a small amount of Dielectric grease. That is where I would start. Good luck.

 

Is it a thermomking? You should hear a really fast clicking noise along with the buzzer sound when you first switch it on , the clicking sound is the fuel pump priming up . i did not hear that in the video. Mine sounded exactly like yours , cranking and cranking and cranking , never turning over would turn over ans fire for a couple seconds and then shut off. Bad fuel pump. They are easy to replace. The 2 bolts you see on the front of the frame there, should be the fuel pump if it is like mine.

 

You’ve lost prime and they are a pain to get going again. I would confirm that the lift pump is working, then cycle it about a dozen times without letting it start. There’s a Phillips screw head on the banjo bolt for a injector line. Let it spin over and crack the line to let air out and be ready to close it when it starts to run.
@reeferwrencher

 

Lost prime and as stated above they can be hard to get going.A surefire way to get it going is to crack the 11/16 fittings on the injection pump and jump 12 volts to the fuel pump and bleed all the air out.A bit of work but I always hate cranking the hell out of a starter.Good luck

 

Did you change the inline filter in the back corner. If newer version there is a screen
In front corner bottom. Sounds like electric pump not working.

 

It could be fuel shut off solenoid. You can unbolt it to see,it will dribble a little oil.

 

what does the switch say. the control knob that is ac, fan, heat. if it shows red alt. then its about that.