Tripac evo problems charging, varied or no voltage

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

 

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.

 

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.