Porsche Enthusiasts Club Forum

Hi all please help how do you stop dim dip side lights on headlights and headlights up when side lights on 1987 s4 cheers.

Hi Potdog

First off that is correct behaviour for 87-89 cars, in accord with uk lighting regs at time which called for dimmed headlights when sidelights on.

It is legal to change it as legislation changed.

But need to confirm you have all the parts for proper operation. Pull back carpet over the central electric panel in passenger footwell. On left side (under moulded section of carpet) you can see the big ignition and injection computers.

Now bolted to top of frame for the computers, yiu should see silver bix suze if fag packet. Supplied by Hella, and will have "DIMM" written on it between 2 othrr bits of German

Please confirm you have located this and I'll continue...

Thanks Stratfordshark have located Hella

Excellent no one has been in there meddling.

This is like giving instructions for bomb disposal!

Right near that Hella box you will find the coding plug for dim-dip (the box just just reduces voltage to the headlight bulbs). It is a small white 3 wire plug labelled "Adapter fur Codierung".

It should have a little plug jammed into it, which is bridging terminals 2 and 3 of the plug. You need to:

- remove the plug bridging 2 and 3

- make up suitable wire so that you can bridge terminals 1 and 2 instead (terminal 1 is the currently unconnected terminal)

- finally unplug the Hella module and keep as souvenir

Please let me know if that allows you to turn on sidelights without headlights rising and on dim. Also check that headlight wash still works (if you are not bridging the coding plug correctly they won't)

Thanks Strafordshark all works fine.

Thats great news Potdog.

Do think of taking your car to East Mids TIPEC meets and events if you havent already- lots of knowledgeable owners who can also help out (did you take your car to national event at Hatton?).

Cheers

Adrian

Doing a big refurb full paint leds cut into front bumper twin exhaust in rear bumper stroseck style bonnet loads of parts window scrapers etc. Hope to have it done by 1st july to go to Chattsworth to Porsche GB club meeting thanks again.

Hi Guys,
I didn't quite understand the OP's request. Is this 'mod' to stop the headlights popping up when you turn your sides lights?

That's correct - for model years 87-89 they had to comply with uk lighting regs. They stipulated the so called "town beam" or dim headlights should come on with sidelights. That regulation was subsequently abandoned - the thinking (which makes a lot of sense) is that if it's dim enough for sidelights then you should have dipped headlights on at full power anyway