My 2007 H3 has a battery drain problem that seems to be from the headlight switch assembly. When battery is fully charged all lights function with engine running. When left overnight the battery is draining and when I get it started the drl don't always come on and the fog lamps mal-function intermittently. That is the reason I believe the switch is draining the battery. This occurred with an older battery and also with a brand new one. My alternator appears to be giving my battery a full 14+ volts of current at idle.

 

Welcome to HF.

It could be your suspect switch, but that would be uncommon.

Are you still trying to use the crappy azzed OEM Battery Terminal Connectors? If so, get rid of them and replace with a quality aftermarket set like Stingers or your favorite brand. That is the #1 first mod to do to every H3/H3T. Look it up. Known issue to cause multiple electrical Gremlins.

Take your switch out and clean the connector(s) and switch connections with CRC Electronic Cleaner then test to see if that made the difference.

Good luck.

 

Good to know about the OEM cable connectors, but I've had my H3 for over 9 years and haven't had a problem before. Also I am now 76 years old with serious back problems. Any tips on easy light switch removal? (P.S.I STILL wheel the H3 pretty hard)

 

Fully charge the battery then test parasitic draw. Plenty YT vids to guide you:

 

That you know of.... the OEM Terminal Connectors are all chit, junk, crap, garbage, lousy, worthless.... you get the idea.

It isn't a matter of if they fail, only when.

On the switch removal, do the YouTube thing.

Julie need a vacuum, her floor mat is cruddy big time.