Originally Posted by Bagger97
Anyone ever hear of the Master battery switch have an intermittent failure? Sometimes lights will still be on with switch turned off.
If your talking about the batter disconnect switch, also known as the salesman switch, all it does is turn a high current relay on and off. The relay is probably failing.
Pull the switch. Should be three wires. One wire should be hot, the other two should be momentarily hot, depending on which way the switch is pushed.. One will energize the relay. The other will kill the relay. If the power coming in is fine, and it sounds like it is since when you have it on, the lights work, check both sides with a VOM. The hot one should transfer power to one side, the other will either also transmit power, or brake the ground.
Question. When you first turn it off, do you still have 12v power or does it shut off and then randomly come on? If you shut it off and it doesn't go off, it is likely the relay. If it goes off but then comes back on, it could be the switch or it could be the relay.