Yet Another Headlight Thread

[510rob]

BE-5

[510rob]

BE-40

[510rob]

Here is a crude sketch I made of the somewhat unconventional headlight wiring in our cars...

[510rob]

Was your car an automatic car originally? Sometimes they have some extra mumbo-jumbo wiring for kick-down or emissions or whatever.

[Rush]

Wow, Rob! Thank you for those! That is some incredibly interesting information! More great pages saved in my car file! I'm going to spend some time absorbing it.

As far as I know, my car was never an automatic but I don't know if there are any tell-tale signs outside of, well, having an automatic tranny. Lol!
I did have an assortment of weird relays but if I recall, they were things like carb switch and emissions garbage.
My wiring looked like a drunk monkey did it so I had to clean up a lot.

[Rush]

I took apart the column & cleaned the stalk contacts again. No change. The high beam indicator comes on, so it seems clear the stalk works properly. I can also hear the relay click onto both low and high positions.

After all of this, maybe it HAS to be my LED headlights? I don't know. My outers work beautifully on lowbeam. I might have an old sealed beam in my parts tote. I'll plug that in & see if that'll change anything. Perhaps the LED lights have too low a draw to trigger properly . If I discover that's the case I'll have to run a resistor and/or maybe a diode so it can't backfeed.

To the bat cave!

[Rush]

*Insert facepalm here.*
So it’s not wiring or the car’s system. It’s the leds.
Now I need to learn why and if it’s a resistance issue, what to add or maybe it’s a current back flow in which case I’d need a diode.

Hmmm…

[bradicuss]

I agree, it's something with how the leds work. My 72 is close to yours with a similar headlight setup. I spent a bunch of time(maybe not as much as you have) last year chasing and experimenting. I finally gave up and wired a lighted toggle switch and called it good. Works great...actually better for flashing bad drivers.

[bertvorgon]

All I remember...on my 510 I had LOW voltage issue on the back tail lights..they would not fire till I figured that out...I think it was around 10 volts...our old wiring and corroded connectors.

My vintage Boler trailer, which I converted to LEDS, both internal and external, dove me CRAZY on one side as the original wiring...which WAS CORRECT, was actually reversed on that side, that the polarity was reversed..lights would not fire..polarity is the game with LED lights!!!1

[Rush]

Yikes, Keith! That must have been awful! Who'd even think that'd be the problem?! I've also done the polarity switch-a-roo, but unfortunately, no luck.
On another note, I had a 13' Burro (just about identical to the Boler). It was the cutest little guy, I loved it! I called it Eggy.

Bradicuss, it's so frustrating, for sure. I think there are 2 solutions; one, add a load equalizer (basically a 1000Ω resistor, I believe), or two, the typical new wiring/relay upgrade.

Once I get this sorted out, I'll do a writeup. Hopefully, it'll save someone else the tail chasing!

[510rob]

hold on...

An LED is essentially a diode. If you have sufficient forward bias voltage to cause the diode to flow and sufficient current flow the hold that voltage, then the LED will produce 'light' (and heat).

1) disconnect all four of the headlight connectors from the bulbs.

2) push the headlight switch OFF.

3) confirm that you do NOT have +12V at the Red/Blue wire on the left side headlight connector, and the Red wire on the right side headlight connector.

4) pull the headlight switch ON.

5) confirm that you DO have +12V at the Red/Blue wire on the left side headlight connector, and the Red wire on the right side headlight connector.

6) push the headlight switch to running lights mode (the 1/2 way position). Why? Because the coil for the [low/high relay] draws +12V power from the running lights, then grounds (or doesn't ground) through the column switch...

7) put the column switch into LOW beam mode.

8a) measure the resistance to ground at the Red/Black wire on each of the to dual-beam headlight connectors. should essentially be 0Ω
8b) measure the resistance to ground at the Red/White wire on each of the to dual-beam headlight connectors. should essentially be ∞Ω
8c) measure the resistance to ground at the Red/White wire on each of the single-beam headlight connectors. should essentially be ∞Ω

9) put the column switch into HIGH beam mode.

10a) measure the resistance to ground at the Red/Black wire on each of the to dual-beam headlight connectors. should essentially be ∞Ω
10b) measure the resistance to ground at the Red/White wire on each of the to dual-beam headlight connectors. should essentially be 0Ω
10c) measure the resistance to ground at the Red/White wire on each of the single-beam headlight connectors. should essentially be 0Ω

Confirm these things first.

[Rush]

Thank you, Rob! I'll head out to the garage in a bit and report back.

[Rush]

Ok, so far, so good. All tested as you said. On High it was 008 on R/W at all connectors.

[510rob]

I remember there was an issue with some headlights years ago where the rear case/body of the headlight was grounding to the chassis via the mounting; the 510 wiring is set up to switch the power on the high side and the beam selection on the ground side so if the bulbs ground out via the chassis, then that nulls the relay.

Can you post a picture and part number of the new LED headlights?

[Rush]

Hmm. That's interesting! I didn't know that. Maybe I should try isolating the mounts on the inners?

I don't have a part number since these are like Amazon lights. This isn't the seller I got them from but I believe these are the exact same lights:
https://www.ebay.com/itm/386284165036?_ ... QXR7BD54W5