What do I Look At?

[arcticfox2005]

Our 2012 Winnebago Access has an intermittent problem - sometimes the engine charges the house batteries and sometimes it doesn't. Recently after being on the road for 2 days, 500 miles or so, the house batteries were at 11.8 volts. Other times, same conditions, up at about 12.7 volts.

Any idea where I should look? About 3 years ago the switch that is supposed to isolate the house batteries when parked for an extended time appeared to not be working. Could this be related to the problem?

Bill

 

[winniman]

Someone is not accidentally turning off the salesmans switch are they. It would shut off the house batteries. Im not sure if it would stop them from charging from the alternator, but it will stop the converter from charging them when plugged into shore power. Just a thought. I dont understand why they put the house disconnect, {salesman switch}, right inside the door where every greenhorn is constantly messing with it because they think it is a light switch. Why not put it on the opposite side of the door, or somewhere slightly out of the way.

 

[shane102]

If at times the  trucks charging system is not charging the house batteries then something may be loose and not making a good connection all the time. Or corroded enough to cause issue. 
What type of isolation set up is it (diode or solenoid switch)  Both could have issue.  Diode could be on its way out and only intermittently working.  Contacts inside solenoid may be worn or corroded and not making good contact.  What make of truck do you have.  Its fairly easy to trace the one wire that controls the charging from vehicle to house bats.