Alternator sense wires

Near dead batteries will do that. Bad alternator regulator will do that. Bad inverter meter will do that. Have you tested the power from "new" alt with a normal volt meter? If no, why no? How long alts serve on your engine before they have to be replaced? What is the reason for them to be replaced? How old the batteries are? Is the alt rebuilt "new", or new "new"?

 

IIRC you have a Cascadia? If so, open the PNDB fuse panel door. Check the fuse labeled "alt sense wire"

 

Sense connect terminal should preferably connect to the battery bank but it can be jumped to the large + output lug on alternator

 

Gliders can be anything in terms of powertrain options.

What alternator do you have on your truck? 36SI....28SI??

There are ways to look up the pin outputs and their function--this is rather easy if you know how to research them. I can help.

 

You should have the battery voltage on the sense wire. The wire needs to be on the S terminal and hooked up directly to the battery positive terminal.

The other wire is for the alternator light or a relay.

The capped terminal on the top is for a tach sense wire.

if the sense wire is in the alternator light terminal “L”, then you may see high voltage out of the alternator.

That said the sense wire is usually the larger of the two, which makes it look like it is on the wrong terminal.

the best way to find out is take the wire off the sense terminal, check for any voltage with the key off, there should be voltage if the wire is the sense wire.

 

Here is a diagram