Can the late foglamps from a '75 be converted to LEDs ? If so where ?

How deep is the enclosure of the fog light? I've been contemplating making an LED fog light for the early cars. The same circuit would work for the late cars.

If anyone has an extra early or late fog light sitting around, I'd like to get one of each to design the PCB to fit inside.

The board I'm designing for the early cars will have 8 Cree XPG3 LEDs, a step up switching converter, and a heatsink. I'm planning to run the LEDs at 0.5 to 0.75A which should be plenty bright.

I'm too lazy to pull the fog light from my '71 to fit the board so I'd like to see if anyone has an extra one they'd like to sell.

Jerry - I’ll send you a set of early fogs or two so you can make me one and keep one for yourself. PM me your address when you have s minute. Thanks, mark

@Spoke

The problem with LED is in order for them to be bright enough they are quite large usually incorporating a huge heat sink and sometimes cooling fans. This makes them near impossible to fit narrow structures like the 914 fog lamps.

You can get LED bulbs nearly the same size as the stock bulbs, but they are worthless as for providing enough light to work. I found this out after wasting a bunch of money on junk LED bulbs.

Jerry/Spoke knows what he’s doing.

Thanks Mark. PM sent.

For the early fogs, I'm only going to have 8 LEDs with a heatsink on the rear of the board. It will have to be a thin heatsink to fit. Plus all the dc-dc converter components will be on the rear of the board beside the heatsink.

With a spare enclosure, I'll print the board with components on it to check for fitment.

I'm in for a pair at almost any price point.
Let there be light..

I put a Led bulb in and wired it to the existing harness. Brighter than stock by far

Let me know when you start selling these. I want a few sets.

For late model fogs would you do a rectangular board like you did for your brake light boards? (which I have and love, BTW.) Would you be able to fit more LEDs based on the layout?


P.s. If anyone hasn't used the euro front led boards from Spoke, get 'em. They are great. The white portion is bright enough to use as a driving light.

The board for the late model rectangular fogs would have a board with rectangular shape. Not sure about adding any more LEDs as the round fogs would have mainly because of power dissipation and heat removal. I would try to keep the overall power dissipation to about 8W or 1W per LED. The LEDs would be backed by a heat sink and the drive circuitry would need to fit around the heat sink.

On the headlight I designed for the 356 owner, I was burning about 20W with 19 LEDs. At room temperature I measured PCB temps approaching 120C or about 100C above ambient. This was too much so I lowered the current in the LEDs and brought the temperature down to less than 100C.

The 19 LEDs running about 275mA were quite bright and were brighter than the headlight on my road car.

The goal with these fog lights would be to run the LEDs at 350mA which will be quite bright.

Let us know when they go into production and I'll take a set. Black board I assume? I'll be a test case for you, if you want.

I always considered that converting the fog light to DRLs would be a good safety feature. I never found the original fog lights to be very effective, but also the car isn’t being driven much at night or in the fog.