Headlight problems 1966

[Bill S.]

1966 I am having problems with my headlights both lights come on can not get low beams I have replaced pigtails/replaced dimmer switch/replaced headlight switch/replaced engine wiring harness but still get both lights lit. can use some help I am running out of things to fix this is a great pain

[Greg T.]

Re: Headlight problems 1966

I would test your dimmer switch with a multi tester to make sure it's working. Maybe try a buddies who knows his works.

[Joe C.]

Re: Headlight problems 1966

Did the problem occur before you replaced the extension harnesses (pigtails)?
Where did you buy the pigtails?
Were the pigtails marked "L" and "R" ? If so, then there is your problem. They should both be the same.

[Stephen L.]

Re: Headlight problems 1966

Did the lights work correctly before you replaced the various items?

I think you may have the ground lead on the wrong pole plug in the low beam plugs (outside bulbs) Look at your wiring diagram very carefully and insure that the ground lead is connected to the common pole on the bulb. You probably have it reversed with the high beam pole. You should be able to "view" the common pole in the bulb. It will be on the left viewed from the back of the bulb. This would be the black lead.

[Joe C.]

Re: Headlight problems 1966

Did the lights work correctly before you replaced the various items?

I think you may have the ground lead on the wrong pole plug in the low beam plugs (outside bulbs) Look at your wiring diagram very carefully and insure that the ground lead is connected to the common pole on the bulb. You probably have it reversed with the high beam pole. You should be able to "view" the common pole in the bulb. It will be on the left viewed from the back of the bulb. This would be the black lead.

If you look at the GM wiring diagram closely, you will see that it is incorrect. The Lectric Limited laminated poster contains the same error that appears in all of the GM publications. The black/black-light green are swapped, incorrectly, in the diagram, so that the Left and Right low beam terminals are mirror images of each other. The diagram for the right side headlight beam connector is correctly drawn. The left side connector contains the error. The problem occurs when some manufacturers reproduce the pigtails in accordance with the incorrect diagram.

[Bill S.]

Re: Headlight problems 1966

had the problem before I replaced all the items

[Bill S.]

Re: Headlight problems 1966

even bought another one didnt work..... still have problem

[Bill S.]

Re: Headlight problems 1966

I'll check it out

[Bill S.]

Re: Headlight problems 1966

on the dimmer switch what is the correct wiring. I have one with three wires maybe they are hooked up wrong cfauseing the switch not to work properly. which on goes on the top and which ones go on the two bottom

[John H.]

Re: Headlight problems 1966

on the dimmer switch what is the correct wiring. I have one with three wires maybe they are hooked up wrong cfauseing the switch not to work properly. which on goes on the top and which ones go on the two bottom

Bill -

If you look at the dimmer switch connector from the wire entry side, the single cavity on top should have a light blue wire (feed from the headlight switch); for the two cavities on the bottom, the right side should be light green (high beams), and the left side should be tan (low beams).

[Bill S.]

Re: Headlight problems 1966

Thank you Jjohn that made the difference a is well thanks again for your assistance