Tripac evo problems charging, varied or no voltage

Yes, that's what my alt looks like. I'm testing the voltage output by turning it on and putting the multimeter on "1" and grounding the other. The belt is in good shape.

 

You should have a wire from 1 to 4. Make sure that wire is not broken.

 

1 to 4? Do you mean 2 to 5 on the diagram?

 

No don’t do that.
There should be a wire from the two pin plug,position 4 going to the output 1.

 

OK we had problems with a few of these on the older trucks we had. What you may want to do is to first clean all the grounds on the unit and go to the frame or battery - depending on who did the installation. Once those are clean, check the sensing fuse, and the connector going into the harness to see if that's not corroded, we had two that were. Once that's ok, then check the main fuse holder by the batteries to make sure that is clean and the cable ends to make sure those are not corroded. These cables are made at installation and we replaced a bunch of them through the years.

If it still is a problem, then check the grounds within the box itself, and make sure there is a clean ground wire from the alternator to the engine and the engine to the negative cable.

 

Where can I find the sensing fuse on an evolution?

 

It should be at the battery end of the cable from the unit. If this is a 'factory' harness, it should have two wires, one is the thick wire going to the fuse block and the other is for the battery sense line.

 

I think I found the problem. I took the grounding strap off and it was pretty frayed up on one side. Tk said to find a b12G strap that's 4 Guage for replacement.

 

Ok, so now I'm really confused. When I turn the APU off at the three knob controller the fan turns on automatically.

 

The current sensor (401491) itself is destroyed. Didn't catch it when I was looking at the fuses. Even when I checked the sensing fuse I didn't realize that sensor itself was messed up so badly. Thermoking wants $400 for the part and I can't find one aftermarket. Tk really sticks it to you in the parts department.