VCCA Home Forums TECHNICAL - GENERAL Electrical - 6 volt Hi Beam problem

Hello All!
A new issue just started on my '51 concerning the hi beam headlights- they won't turn off. I can't switch to low beams. I removed the dimmer switch and thought that the problem was in that but it checked out perfectly. There is continuity from the "BAT" lug to each of the low and high lugs as the switch is operated. I put the switch back in and, on the car, it doesn't seem to disconnect from the high lug. What I did find is that with the wires off the switch, there is continuity from the low beam wire to the high beam wire. This doesn't make sense. I removed the headlights to see if perhaps there was a short in the bulb. Same thing. Electrical is not my strong suit so any help would be greatly appreciated.
Jeff

Hi Jeff,

Take a look at the two terminals just in front of the radiator. It is possible that one of the lugs is loose and allows the wires to "short".

Your headlight bulb has three terminals. One powers the high, one powers the low and the other is the ground connection. So there is continuity between the high and low terminals as they are both joined to the ground terminal. If one of your headlights has a poor ground both high beam and low beam can light at once. This can affect both sides.

Thanks for the reply. I will check this out tomorrow.
Jeff

Thanks! Should there be continuity from the high beam wire to the low beam wire when both are disconnected from the dimmer switch?
Jeff

Hi Jeff,

In Old216's post he noted that there will be continuity between them because they are both connected to the same ground terminal within the bulb itself. So the wires leading to the headlight terminals will show the same continuity.

Try disconnecting all headlights at the globe/sealed beam then check which wires have power (should only be 1 on each side) and will change when the dipper switch is operated, 1 wire will have no power or ground connection and 1 wire should have a good connection to ground.
Tony

Thanks to both of you for your help. I will remove the headlight bulbs and check as you suggest at the terminals. I will let you kn ow the results later.
Jeff

Update- problem solved! It turns out that the high and low filament on one of the bulbs were touching. A different bulb solved the problem. Thanks again for all your suggestions.
Jeff

Thanks for putting a "light" on the answer.