Author Topic: W116 300SD Fog lights with LED retrofit.  (Read 181 times)

Engineerd3d

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W116 300SD Fog lights with LED retrofit.
« on: 03 March 2021, 02:37 PM »
I was looking at my car after I bought it and something seemed missing. I could not put my finger on it, although I am new to the whole vintage Mercedes thing. Turns out the PO removed the fogs and tied the wires under the chin. A quick google confirmed that yes these cars should have proper fog lights. Some have amber lenses/reflectors other do not. Out came the multimeter and indeed the wires are there and fully functional.

Next came the quick e-bay search, turns out a busted set is worth a couple hundred dollars? Even if they were mint its more than I am willing to spend. The OEM Bosch units are made of 40+ year old plastic and very prone to being broken anyway. I decided to search for a set of square aftermarket lights, turns out that is easier said than done as most of them these days look like an alien designed them, therefore they would look out of place.

The only suitable set I saw were made by blazer and these checked 3 out of 4 boxes.
1 - Affordable
2 - Glass Lens
3 - Vintage looks
4 - Chrome bezel - Missing.

I guess the blazer (DF1075KB) fogs have to do for my needs. So I ordered a set, a few days later I got the set and they look relatively decent. I am quite happy especially for 15bux, then I decided to test them out, turns out the h3 bulbs are in the neighborhood of 55w per, that works out to be about 10A on this car. Based on my reading the alternator unless upgraded is only 55A total. So 20% of the power domain wasted on fogs is not my idea of fun. I decided to find a set of LED h3 bulbs that would fit, the constraint is these bulbs cannot have a protrusion in the back or have any sort of active cooling as there is no space or ventilation in the housings. I finally found a set of H3 bulbs that fit the housings but the down side is they are about 2/3 as bright as the halogens. Good enough for my needs and they consume less than an amp combined. Win win in my book, I ended up buying amber leds for a deep amber color.

The next part was mounting them. Being a man that never takes the easy route (Just drill a hole in there) I decided I wanted an adapter bracket to utilize the factory holes. At first I thought I would simply make it out of flat sock, but I would not be happy with that. So a bit of sketchup and measuring I had a workable design I could 3d print. I made the 3d print file public as well if someone wants to replicate this. (https://www.youmagine.com/designs/w116-1972-1980-mercedes-300sd-fog-light-bracket-for-blazer-df1075kb-fog-lights)

Attached are the pictures of before and after the fogs went into the car. I am quite happy with the result. Overall I am very happy with the result. I am taking the car out for a drive this evening to check out the new found clarity as well as aim the fogs better.

Now if someone wants to watch a youtube video of the process above this is the link. https://youtu.be/7aJwds9D65Y

revilla

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Re: W116 300SD Fog lights with LED retrofit.
« Reply #1 on: 03 March 2021, 07:40 PM »
1 thumb up for each, bravo!
Love the plate too.
Robert
W116 1977 280SEL & 1979 280SE

revilla

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Re: W116 300SD Fog lights with LED retrofit.
« Reply #2 on: 03 March 2021, 09:24 PM »
For your grille you'll need these.  Available and not pricy. 

https://www.auto-doc.fr/trucktec-automotive/8057290.     (Europe)

https://www.partsgeek.com/ss/?i=1&ssq=1168880185&x=19&y=11.   (USA)

https://www.autohausaz.com/pn/2019882578. (plastic fasteners, USA)

Cheers
Robert
W116 1977 280SEL & 1979 280SE

Engineerd3d

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Re: W116 300SD Fog lights with LED retrofit.
« Reply #3 on: 04 March 2021, 01:45 PM »
Thank you for the info on the grille. I will order a few parts asap and fix it including the plastic clips.

Thank you for that info. The kits for these seem to be all over the place from 50$ to a couple hundred bucks. I will order them now.