my alternator is not charging, but if i tap it , it will start to charge . I also notices it gets warm .. is this normal... i just replaced the two house batts one of which had a short . and before it had shorted out . the alt, worked fine . so what I'm thinking is i need to just replace the ALT . And why tapping it, makes it work ? . also my small auxiliary air-compressor is shot. what should i do to maybe upgrade it ? . thanks all :)
I'd start off by disconnecting the batteries and checking for corrosion or loose terminals on back of alternator, and where these wires connect to the coach. It's normal for the alt to heat up in operation when charging hard. Sounds like you have an intermittent connection.
Also, pay particular attention to the small sense wire-- at both alternator and battery isolator ends. Much easier to break/come loose than the large B+ or other larger gauge wires.
Your slip ring brushes may be worn or sticking