Hi, all. Newbie to the forum. I have an 86 D350. 360 Manual trans. When I left work this morn I went to hit my dimmer switch to go from low beam to high beam and my headlights turned off. Hit the switch again and they went back to low beam. I tried every few mins on the way home and they turned off every time. The tail lights n running lights n all stay on, just the headlights turn off. This is a brand new issue cause last week they worked fine. Thanks in advance

 

Sounds like time for a new dimmer switch.

 

Seconded. Definitely a bad dimmer. My will do the same thing if it has been a while since I've used it, but after a few cycles to clean off the corrosion it works fine. You can try spraying some electronics cleaner inside and cycling it a few times and see if that helps, but if not a new switch isn't too expensive.

 

Took it off, ohm'd it out, cleaned the contacts then stuck it back in and it worked. Back in business.