1999 LeSabre Cannot turn off high-beams via on/off switch

99 Buick LeSabre
I only have one low-beam working, the other low-beam bulb went out today. When I switch to high-beams , the high-beams come on , but I cannot turn them off via the manual light on/off switch on the door panel. The Twilight Sentinel works properly, and will shut off the high-beams per switch setting.
During the daytime , the high-beams will just stay on till I turn off the car, manual headlight switch wont turn them off :frown:

Ok, so you can switch to hi beams and back to low beams?

It's just that you can't turn off the lights manually, if in hi or lo position?


During the daytime, your DRL come on automatically....these are your hi beams, running in series, instead of parallel, thus they are at half brightness....you can't turn them off with the on/off switch(I think they go off if you apply the ebrake in Park)....

So you have one of three possibilities....either a bad on/off switch, bad lamp control module, or the circuit between the two is grounded.....