The Stovebolt Site Forums The Shop Area The Electrical Bay Headlights only work on High Beam now

1941 original 216 6 volt. Lights worked fine on my last drive and now theya re only on during heigh beam. I am not super mechanical, so guidance for dummies would be greatly appreciated.

I would take a look at your 'dimmer' switch. It switches the power from the dash light switch to either hi or low. If you have voltage on both outputs of the switch I would look for an open/broken wire or wire connector between the lights and dimmer. Don't think bad ground would be it as the hi beams work.

Another very slim possibility is both bulbs have low beam out. Check at the bulb for power to the low beam side of the bulb.

I had both bulbs go bad on low beam one time and about drove me nuts till I pulled one out and checked the power at the bulb connection.

Wound up replacing both bulbs to get low and high beam lights back.

Always start first at the light not working to make sure you have power to it is how I work an electrical glitch. If you have power to both low and high beam sides of the connector, then the bulb may save you a lot of work.

If no power to the connector, then work your way back to the connector on the fire wall on the drivers side to see if there is power there. Or go directly to check the dimmer switch.

Another easy spot to check is the dimmer switch. It is possible the dimmer switch has burnt the contact inside for the low beam side. You'll have to have someone inside the truck to activate the dimmer switch to make it a bit easier.

Both ideas have merit and I've experienced both. Since it's very rare for both bulbs to burn out at the same time, if it was me I'd start with the dimmer switch since it lives in a very inhospitable place and it consists of moving parts. It's common for the internal parts to corrode and/or wear out.

Unplug the dimmer switch and clean the contacts both on the switch and the plug end. Then plug it back in and watch the lights work as designed. As Tiny said the switch lives a filthy life.

You can check the low beam elements of the bulbs without the disassembly of much. Make sure the headlights are off. Disconnect the low beam wire at the junction block on the inner fender (if that is where it is located on a '41), and use an ohmmeter between that wire and a good ground. This will read the resistance through the element. No reading? Bad bulb.
Carl

You guys are all so awesome! Thanks so much. I'll let you know the verdict.

New bulbs. New dimmer switch. 1947.5 3800. Will check wires. Dims are off.