Retrofitting a lightened head light switch to an earlier car

[austria3]

I always liked the look of the lightened head light switch on the later cars (994, 993) and never did understand why it took Porsche so long to make such a simple thing happen.

So I wanted to fit one of these switches to my car. For financial reasons I opted for the cheaper 944 version with the part number 944 613 531 00 (the 993 versions is 993 613 531 00) and a used one from ebay.




first task – wiring
The connectors on the backside of the switch are totally different and not interchangeable, the colour and codes are mostly – depending on the year and model.



My goal was to keep the stock connectors and make some kind of adapters so I could rip it just out in case I don’t like it. I bought
1 connector housing 944 613 531 01
12 connectors 944 612 548 00
and spent quite some time over wiring diagrams to built the adapter



and tested my theories




Second task – mounting to the dashboard
Not only is the wiring different, the dimension of the switch is quite different too



First I had to enlarge the hole in my dashboard form 10mm to 17mm


Then I had to design and print a nut that fits the new switch and the hole in my dashboard


Had some trouble printing a perfect M16x1.0 thread, so I had to re-cut it (the amount of chips in the picture is from two such nuts)


Test fit:



Task three – dimming the instrument lights
The newer cars have an extra dimmer switch so I had to make one too. Thank to @rothaus who provided the data for the right dimmer for his dashboard led-lights (250 Ohm, and 5W, linear). The one I bought didn’t look like the one from the wiper, which I took a reference since the knobs are the same (beside the symbol)

from left to right: dimmer in its original form, wiper interval for reference, after some time with a file and a handsaw

[austria3]

After removing the speedometer the wiring connectors for the dash lights could be found (red and green arrow)


The dimmer found its home in the hole of the EGR-light



task four – knob
The 944 knob looks totally different to the 911 knob, so I had to get creative. In my girlfriends toolbox I did find a punch-set with the right diameter.
After the first hit with a hammer:

Viewed from the front: Left: punch, top: inner… , bottom: outer part of standard knob, right: 944 knob

After one more hit with the hammer:

Right top: outer..., right bottom: inner part of 944 knob

Glued together with some seam sealer it did look like this:



With a self-designed and printed cover it looks like this:


(yes I have also added a light for my ignition key and I replaced the oil gauge with an later one)