Technical Wiring Gremlins- headlights- help please

@jaracer may be on the right track. I would look closely at the connector plugs to the headlight switch, especially the spade connector for the feed from the switch to the headlights. Depending on how this was wired when the toggle switch was installed, it could also be the power feed to the switch. From your description, that would seem the most likely bottleneck in the system. If we knew how the toggle switch was connected, that could suggest the failure point. A failure of one of the wire terminations at a spade connector is possible. I've seen factory crimps so poor that they were only making contact through a few strands of wire. They can also be loose enough to intermittently lose contact due to vibration, which kinda sounds like what's going on here. 2X on what @jaracer said about checking the plug for heat damage. If everything worked with the toggle switch, that seems to rule out any problem "downstream" from the switch, and he's replaced everything connected with that except for the wiring.
There is another possibility mentioned by others here. If the switch is imported, it is highly suspect. I owned a NAPA store in my past life and am no stranger to defective parts. NAPA was always pretty good on parts quality, selling almost all US made parts back in the day. I had a customer bring in a headlight switch and ask for a replacement. He said he got it at Auto Zone, everything fit but it didn't work. Asked him why he didn't take it back for warranty replacement. He said, "I would, but this is the fifth one I've tried from there, and none worked." He came in a few days later and told me that the US made Echlin switch I sold him worked perfectly. He was a regular customer after that. Don't take this as a plug for NAPA, just be advised that imported electrical parts are questionable.

 

Back to my faulty 1157 bulb, that one had a strobe effect to it. I've only seen it that one time. I had some used bulbs around and was able to narrow it down quickly after driving myself nuts chasing everything else. I think it may have been an induced feedback thing with a bum element.

 

Keep in mind guys that the toggle and the stand alone wiring was the cure. Steve removed it because he thought it was hokey. He put it back in the original oem configuration and the problem returned. I haven't seen him to ask about the brand of new parts that he used yet. I agree that I would start with an OEM headlight switch and go from there.

 

So we have used 2 different stock style switches I take it but the problem is the same. How much of the original circuit did the toggle switch use?

 

Steve sends his thanks. He followed this thread and spent yesterday wiring up some relays as per y’all’s advice.
So far he has an hour of run time with no issues.
Just thought I would update this with the end results.


He said the goal is to tidy it all up and make it like sanitary.

 

Since the headlights do not go completely out .I would say the trouble is in the rear lighting.
An intermittent short in the rear would make the headlights flicker but not go out.
Worked on taxicabs and found the wire to the plate light would get shorted on the pan behind the rear bumper.Cabs always getting bumped in the rear.Just a thought.

 

Thanks for the feedback on the fix. We so rarely see that!

John

 

Check the Harness plug in for the head light switch. The Bakelite plastic around the wire terminals got hot and melted away exposing the wires to each other and they will arc across to each other, especially the headlights. A lot of Fords and GMs had this issue back then. I know. I owned a number of them. If that's the problem. after you fix it a relay on the power impute side would still be a good idea. Up until the late 70s Ford even still had 6-volt instrument panels with a voltage reduction resistor to knock the 12 volt lead down to the 6 volts needed. I love my Fords, but their electrical engineering department could have used a few more lessons in school. lol Larry

 

Thanks Larry, I think he put a new harness in it.