Headlight Switch Problem

[wedel456]

Problem:

Just finished my dash install today and having a problem albeit very intermittent, with my headlight switch.

Background:

I have two *led* lights on the wings of the dash. When the switch is not installed in the dash everything works correctly 100 percent of the time.
When it is installed in the dash the courtesy lights remain on, even when the courtesy switch is in the off position, the entire time and flicker when adjusting the pull until you get to the on position then they remain solid. When not adjusting the pull the lights do not flicker yet remain on.

I have confirmed ground is correct and my headlight, parking lights, and instrument lights are all functioning correctly.

Any thoughts?

[Nigel Allen]

The courtesy lights are controlled by the headlight switch. Rotate the knob slightly anti-clockwise off of the detent and the courtesy light should go out.

By the way, the grounding for the courtesy lights comes through the body of the switch and that is why it is not a problem when it's not installed in the dash (which provides the ground to the switch)

Cheers,
Nige

[wedel456]

The courtesy lights are controlled by the headlight switch. Rotate the knob slightly anti-clockwise off of the detent and the courtesy light should go out.

The lights will never go off, not matter what position the knob is twisted when the switch is installed in the dash.


By the way, the grounding for the courtesy lights comes through the body of the switch and that is why it is not a problem when it's not installed in the dash (which provides the ground to the switch.

The wiring is no different installed or not installed the in dash. I am using the default harness with the grounding wire connected to the side of the body, as per the instructions. Something strange is happening and I cannot figure this out.

[Nigel Allen]

I hear your frustration! Seems it might be a mechanical issue with the headlight switch. It switches the ground and from memory I recall that you could view the contact of the switch. Maybe a close inspection with a meter to measure continuity might reveal the issue.

[weendoggy]

How did you wire the lights? The power (bat +) goes to the courtesy light, then it gets grounded via the H/L switch body/ground when activated (or door switch when opened, if installed). I'd double check your wiring.

[wedel456]

How did you wire the lights? The power (bat +) goes to the courtesy light, then it gets grounded via the H/L switch body/ground when activated (or door switch when opened, if installed). I'd double check your wiring.

I am using a IDidIt module (https://www.jegs.com/i/Ididit/535/3100006040/10002/-1) wired very similarly to to how @TedG documented (https://thefactoryfiveforum.com/showthread.php?44022-Russ-Thompson-Turn-Signal-and-IDIDIT-Relay-wiring-schematic):

220038

I am fairly confident that the wiring is correct. When the switch is out of the dash things appear to be working correctly. When I put it in then I start having some issues.

[weendoggy]

How are your courtesy lights wired to your H/L switch, and what style of switch are you using? I can't see how that module would effect that operation unless it is feeding the courtesy light circuit and grounding via the module, and not using the H/L switch.

[edwardb]

Nothing about the iDidit module or the wiring diagram you posted affects the courtesy light circuit. They're powered by the Red-Courtesy-Light wire from the battery (always on) side of the RF panel and grounded by the grey wire out of the headlight switch when turned past the detent. Check to make sure you have always on +12V plus from the Red-Courtesy-Light wire. If so, it's likely a ground problem with the headlight switch. Either the ground isn't adequate or the switch is defective. Not unheard of. That's a knock-off switch that I haven't had great luck with. A real branded Delco D1588 IMO is better quality and I've used on my builds. About $25 on Amazon.

[Jphoenix]

"That's a knock-off switch that I haven't had great luck with. A real branded Delco D1588 IMO is better quality and I've used on my builds. About $25 on Amazon."

I did exactly that on my 289 FIA. Tossed the one for my Coupe in the bin.

[wedel456]

Nothing about the iDidit module or the wiring diagram you posted affects the courtesy light circuit. They're powered by the Red-Courtesy-Light wire from the battery (always on) side of the RF panel and grounded by the grey wire out of the headlight switch when turned past the detent. Check to make sure you have always on +12V plus from the Red-Courtesy-Light wire. If so, it's likely a ground problem with the headlight switch. Either the ground isn't adequate or the switch is defective. Not unheard of. That's a knock-off switch that I haven't had great luck with. A real branded Delco D1588 IMO is better quality and I've used on my builds. About $25 on Amazon.

I know the wiring is correct and the ground is good for it works when it is out of the dash. So dang strange. I have an overhead light that will tie into the headlight switch lights, too, that works off a toggle. Was thinking of just abandoning the headlight switch functionality all togerther; however, I will order a new switch and see if that fixes it.