Just installed a pair of LED Truck-lite headlights. I turn on the lights and only the low beams works. If I remove the left LED headlight and plug in the old H4 headlight with a tungsten bulb, and leave the LED headlight on the right side, then the high beams and low beams work on the H4 and the LED bulb??? On a side note, I installed LED turn signal and tail light bulbs and modified the flasher with a jumper wire. Turn signals and running lights work fine.

I think you need to switch to the LED flasher unit; I don't think the jumper is the best way to approach this.

https://www.spokeworksled.com/product-page/...r-for-74-76-914

This is what was modified, isn't this what Spoke sells? My turn signals and flashers work fine. Do I need a load resistor kit? Forgot to mention my fog lights are separate from the headlights. They only turn on when I pull the fog light switch. The high and low beam work with one halogen bulb headlight and one led headlight plugged in. That would indicate a load is needed to make the high/low beam relay work? Click to view attachment

Bump.

John, the Spokes flasher is for when you put LEDs into your turn signals, it is not related to the headlights.

I installed Amazon-sourced 7" LED headlights, and do not recall having to do anything to make them work; in fact, they work quite well.

https://www.amazon.com/gp/product/B077P56CG8

I'm not familiar with Truck-Lite; can you post a link? Could be something in that product that is incompatible.

Greg

@Geezer914 - Sorry I misread the post. Yeah, the LED flasher is just for the turn signals.

I called Truck-lites and spoke to a tech. He said they should be plug & play. He suggested getting hearlight load resistors. I have LED bulbs in my fog lights. I snipped the black/blue stripe wire from #56 on the headlight switch and piggy backed it to #15. I also grounded the white/blue stripe wire from the fog light relay. Still no high beams. I guess since all the lights are LED I need the load resistors. John C.

I still have the GE Nighthawk LED headlights and they were plug and play.
I only ran into problems when I replaced all my other lights with spoke LED’s. I had to upgrade to a LED compatible flasher and hardwire my turn signal dash lights to the actual turn signal lights.
Love the Spoke LED's and was worth the hassle with the workarounds.

I can’t get my head around why load resistors would be needed on something like 914 headlights.

Use a voltmeter and confirm that the correct pin on the headlight connector is grounded and that the high and low beam pins are correct as well. My guess is that somewhere something has been inadvertently swapped.

I would guess that LED bulbs are polarity sensitive while sealed beam/halogen bulbs are not.

I have the same problem, my high beams don't work with LED bulbs. Since rarely even drive at night. I have not dug into it.

I don't understand it either. I looked over the wiring diagrams and the power source is the same, the only difference is the relay switching circuits from low filaments to high filaments.

But I also don't understand why the turn signal relay needs more amps to simply switch those circuits back and forth. But it certainly does not work with LED bulbs.

Best I can figure, the relay needs more load than an LED provides to be able to function. A parallel resistor will provide that load.

I spoke to John on the phone Friday and he's ordering the resistors. He'll report back when he gets that installed.

The lower the resistance, the higher the load. A large load draws a large current.

V = IR

Better be right or your great big venture goes west
Bad boys rape our young girls but violet goes willingly
The above is used to read the resistor color codes

Adding parallel resistors reduces overall circuit resistance and thus increases overall circuit amperage because there's multiple paths.

Add an infinite number of parallel resistors and you asymptotically approach system resistance of zero, thus approach infinite amperage draw (and crispy wiring).

Calculating parallel resistance: 1/R=1/Ra+1/Rb+...+1/Rn

Since V=IR, given reduced R with the same V potential, I increases.

If what this relay wants is more amps, then it will get it with a parallel resistor.

As I mentioned, if I plug in a halogen headlight on one side and an LED headlight on the other, the high and low beams work. You guys are getting into some dark shit with that V=IR stuff!

Love this thread… wife and I had a good laugh…

Carry on…

The turn signal relay also has a function built in to detect a failed or missing bulb and flashes the turn signals faster as a way of letting you know. It does this by (crudely) measuring the current being drawn. LED bulbs draw so little current that the relay thinks the bulbs are out and either rapid flashes or doesn’t flash at all. Hence the need for an LED compatible turn signal relay.

Pretty certain the headlamp relay is “dumb”. My money is still on the terminals having been mixed up at the headlight connectors. Or perhaps a bad ground on one of the lights and some funky reverse current flow that works fine on an incandescent bulb not on a light emitting DIODE.

Load resistors partially defeat the purpose of LED bulbs.

I put LED headlamp bulbs into my 914 and they work without issue.

Just for the hell of it while waiting for the mail to come, L found an old VW SWF 4 pin relay. I switched out the relay and when I switch the stalk on the turn signal switch, the high beams come on but as soon as I let go of the stalk, the lights shut off. Turn off the head lights, pull the switch, low beams come on click on the high beams, they come on, let go of the stalk, lights go out????

I had the same issue with my led headlights. My fix was to bypass the headlight relay and wire the high beams to a separate switch I mounted in the dash. Works great now.

Mikey 63 could you have a bad headlight switch? I just switched back to the original relay and unplugged one LED headlight and plugged in a halogen light. Low beams and high beams work on both the halogen and LED and the lights stay on.

It might be, but I didn't have a spare headlight switch to try...for the very little time I drive this car at night this fix works for me.

SUCCESS!!!! Installed one headlight load resistor on the drivers side and everything works!

Great that you got it working. Don’t understand why the resistor helped but there’s just another one of life’s mysteries.

1970s vehicles plus LED lights is a recipe for really weird stuff. I have the Trucklite LED headlights and didn't have an issue. I wonder if the fog light relay could cause issues. Mine is disconnected from the high beam.

I disconnected the fog lights from the headlights. Black wire/blue stripe piggy backed to post 15 and I grounded the white/blue stripe wire on the fog light relay.