Commonly used for 80 series land cruisers, when you have fitted an upgrade headlight harness and find your high beam indicator light on dash not working and high and low beams trying to work at same time and cant switch between both.
This is due to normally the upgrade harness will just get signal from one of the original headlight sockets, but if you dont draw power from the other then the above issues will occur, this circuit completer you just plug into the opposite headlight plug and will fix the above issue.
