Combines alternator headaches on 7720

sounds more like have a problem with the guage not the alternator if u can run your lights and still start in the morning you have not a problem with the alternater put a meter on the alternater see what voltage it is putting out should be around the 12.8 13 .2 mark alternater

Possibly the gauge, seen them go bad. BUT---------------- One thing I have found....Check all the connections on your circuit breakers in the engine compartment fire wall next to the cab. I said all because I am not which one is for the charging system. I have found a bad breaker connection will show a discharge.... let me know if this helps.

We put in a new switch and another alternator. It shows better, but at times still shows a discharge. A neighbor told us his did this all the time and he just lived with it. For now we are too. We did replace one breaker too, thanks for the help.