I have a 1987 928 S4.

Has anyone replaced their halogen headlight bulbs with LEDs ??

I ordered "9007 CSP Mini LED" bulbs from Headlight Revolution.

When installed, the bulbs only had "high beams" regardless of the switch/flasher position. I had talked with one of their techs, and they shipped an adaptor pigtail.

I installed the bulbs with the pigtail as directed. The headlights worked correctly . . . . UNTIL I turned on the foglight switch. Then the headlights reverted to "high beam only" again.
Is it possible the "bulb out" warning system is the case of this ??

Any insight would be greatly appreciated.

.

 

Yes LED's headlights can have some un-intended iterations with foglights, aux lights, and high beams. This is a byproduct of the complex circuitry in the headlight realy and the rest of the front lights circuit which rely on grounding through the incandescent filament of a traditional bulb. Since LED's do not have any conductivity whatsoever, it messes with the original design of the system.

Fear not, most problems can be resolved with a little trial and error. There are some threads that cover the specific headlight / fog light interaction issues, https://rennlist.com/forums/928-foru...led-bulbs.html My first suggestion for you is to swap out the 'special foglight relay' with a standard '53' style relay that usually fixes most problems with LED as described in the related thread. This standard relay bypasses the feature that dissables fogs when the highbeams are used. May sure you follow a strict test protocol each time so you cover all the front light scenarios and combinations. Repeat the test at least twice with the car running. I have found that a scenario may work differently the first time. So its best to test multiple times. Also, check your headlights for faint glows when not active. If changing the fog light relay does not work. consider some different LED bulbs. Use a vendor that offers free returns to enable your trial and error. Best of luck I had an 87/88 and was able to get the system to work with several different bulbs.

LED bulbs are a great way to save amp draw to the headlight system. However as others will undoubtedly point out if you are looking for better light, then adding brighter bulbs to the USA spec system (9007 bulbs) is not necessarily going to give you the best results. Everyone says upgrade to H4's (for a large sum of money) and then consider LED's. I've never tried LED's in the USA spec system so I cannot attest to the results, but the logic makes sense, Use the best lens/reflector and then add more light. Let us know how your experimentation goes. Especially if you are able to resolve your issues.

FYI, here is my setup H4 headlights with LED bulbs in all forward facing lights. LED performance varies. The are fantastic and many bulbs outperform their halogen counterparts and there are many options available and the Lumens keep getting more powerful as time passes.. LED H3's used in Fog/Aux locations are still not as powerful as the halogen bulbs. The tech is still evolving in that small packaging. I have found a few the fit in the location that are about the same output but nothing that blows away the halogen bulbs like the H4's.

 

I had LEDs for years and suffered with their many quirks despite trying most remedies - 53 relay, jumped relay, etc. Still had issues including having the headlights on despite being retracted, albeit at low wattage.

About 3 months ago I bought a set of Hella high wattage H4s (100/80) and am completely please with their performance with my 8" H4 lens.


All the best,


Joe

 

I did all LEDs in my 81 Euro S including the headlights (H4 housings) and the lighting was fantastic.



Here's a picture of an 80W (not 55W or 60W) brand new Hella Halogen on the right, compared to the new LED on the left. Ignore the heights of the beams as this was pre-adjistment.




Both LEDs installed and adjusted



Left side - Make sure you have the wires going to the correct bulb terminals, especially if your car doesn't have the headlight plug any longer like mine didn't. If the wires are crossed up, the low and high beams won't work correctly and you'll see the high beam dash indicator glow all the time



Right side



Was going to do the same thing on my 84 Euro S, but discovered the PO installed an HID kit into the H4 housings and the light output is excellent, so didn't change them on this car, but I did do the H3 LEDs in the bumper lights (fog and aux hi-beams), same as on the 81.



Running all clear lenses in this one too that I think cleans up the look of the car


Amber LEDs in the Euro fog light housings. In the Euros the corner lamps are single filament for the turn signals only and the marker lights are an extra bulb inside the fog light housing



When fog lights are on they essentially override the amber parking light so all the projected light is white


Marker lights with headlights up


Fog Lights on with headlights up


Fog Lights with HID headlights on. Whenever I need new HID headlight bulbs I'll get s color temperature that better matches the bumper lights


Fog Lights, aux hi-beams, and HID hi-beams all illuminated

 

Pete, my H4 lights have the rubber cap over the 3 plugs from the bulb. So I must use the adapter from Ed.
Is MY 81 different to 84?
Btw, looks really good!
You found 6 of these tea lights in the old configuration?

 

I don't know about the model year differences. On the 84 I removed the cover, saw the HID wiring and black rubber cap and out the cover back on. The install was done very nicely so I was please stop see that.

On the 79 Spyder I have HIDs in the H4s and different bulbs in the bumper lights. These new H3s actually fit into the housing without modification.

 

I followed the recommendation from Michael Benno and replaced the standard fog light relay with Bosch PN: 0 332 019 103

That solved my problem, everything works as it should.

Thank You Michael.