Porsche Enthusiasts Club Forum

Right then. I’ve been following old recommendations from the PCGB forum on how to cancel the silly ‘dim-dip’ action that 944s from the late eighties have. I’m having trouble getting it to work though, and nobody over there seems able to help figure out why.

Here’s the goal: See how the main headlights pop up when you switch on your sidelights? I want to stop that happening. It was a short-lived legal requirement at the end of the eighties, and it’s not necessary at all now.

Here’s the instructions that seem to work for most people:



And here’s a picture of the successful modification on someone else’s car:


Now, I’ve followed the above instructions, my wiring matches the above perfectly … but it doesn’t quite work as it should.

Sure enough, switch to sidelights and they come on without lifting the headlights. Great. But, switching up to headlights, they still don’t pop up. Damn.

I checked and double-checked, I’ve removed the connection from the dim-dip unit and all my link wires are in the right places where relay G6 used to be. I’ve double-checked their positions against the photo above.

But the headlights no longer work.

Has anyone got any idea what might be going wrong? For now I’ve put everything back to normal and it’s all working just fine.

Just to clarify even if you plug the original module in the headlights don't work. Are they working & not coming up or both?
If the headlights aren't coming up check the relay on the motor, I seem to remember it has a fuse in the relay. Also do a complete fuse check, it's more complex than you think.

Nope, as standard everything works fine.

Standard:
Switch to sidelights = parking lights come on and headlights pop up but do not illuminate
Switch to headlights = parking lights stay on and headlights stay up and illuminate
Switch back to sidelights = parking lights stay on, headlights switch off but stay up
Switch off = headlights pop down, everything switches off

Modified desired result:
Switch to sidelights = parking lights come on and headlights stay down
Switch to headlights = parking lights stay on and headlights pop up and illuminate
Switch back to sidelights = parking lights stay on, headlights switch off but stay up
Switch off = headlights pop down, everything switches off

Modified what actually happens (to just me, it seems!):
Switch to sidelights = parking lights come on and headlights stay down
Switch to headlights = parking lights stay on and headlights stay down (cannot see if they are on or off)
Switch back to sidelights = parking lights stay on, headlights stay down
Switch off = headlights still down, everything switches off

didn't know this was possible (the desired effect that is), will have a go this weekend myself as i think it looks better than lights up but not on

This looks like a challenge, i will look at the circuit at the weekend as i'd like to do this mod..( i've done mod's to disconnect dim/dip circuits on 80's Ford's,,note no headlamp motors to operate)..... but as Jim says this is quite a complicated circuit, i can almost sense a diode pack and latching double pole single throw relays with added double park headlamp motors to attack

That relay in G6 was a diode pack ?

cheers

No it's not a diode pack it's like a hardwired matrix plug, that links up the wiring for different markets. It's a bl00dy complex way of doing it.
I remember a discussion of this on Titanic a while ago.
Because mine is an 87 car with an S2 front, I've got dim/dip & sidelights in the driving lights. I'll have a look at the diagram when I have a mo.

Aye, the relay in G6 was just a set of bridging links, if I’m reading the diagram on top of it correctly.

This mod just changes the links.

Someone on the PCGB forum piped up with a possible reason for my problems with it tonight: Maybe the spade connectors I’m using are not long enough and aren’t making proper contact. Simple, but possible! Not sure where I might find longer ones though. The ones I have came from Maplin, so I need to find an alternative source.

What I’d really like to know is whether there’s a simpler option. Would taking G6 from an older car (pre-dip-dip regulations) work, using that in conjunction with removing the dip-dip box under the dash?

Yeah, as I said up there, I do fancy trying that (can’t find any record of anyone else doing it that way in the PCGB forum archives). No idea how or where I could source the right specific relay though—other than taking one from (for instance) your car and trying it out. Nobody selling relays etc seems to care much for telling you which exact model and year car they came out of!

Be careful there are considerable differences between early & later cars. Also an S2 has sidelights in the fog/driving licence like mine, dim/dip was only fitted for 2ish years I believe 86-88.
The only way I can think of doing it is rewiring the plug (it's not a relay) from a scrap car, that should cover any connection issues.

Might have been ’86–’89, as I have an ’87 and an ’89 car, both of which have dim-dip behaviour.

As luck would have it, I found an alternative G6 ‘relay’ in the back of the garage half an hour ago.


On the left is the standard ’89 plug with definite dim-dip behaviour.
On the right is the other plug I found in the bottom of a spares bag.
The diagram on the other plug seems to match the home-wiring job I’ve been trying to do, according to the instructions that seem to be working for everyone else.

So, I popped in the older G6 plug and disconnected my dim-dip box under the dash.

Still not working as it theoretically should. Same result I had with my own bridging wires.

At least that tells me that my problem isn’t my spade connectors being too short. It’s something else. I also now know that with the modification my headlights are coming on when I switch ’em on, they’re just not popping up.

I have sidelights in my headlights. Doesn't everyone.........

don't think S2's do, but, and this may be an accidental find, my side lights in the headlights come on with the ignition on, but as park lights they don't

S2s do have sidelights in the headlights as well as the bumper. How these work depends on if you are switching them from off to sidelights or headlights to sidelights.

OK just been out to the garage, Haynes manual marks this as a bridge & gives no details not even pin numbers!

Just gone cross eyed ploughing my way through the Porsche book.
Using a 924S 1988 which hjas optional dim dip (uk only!) The bridge plug on the drawing has 1, 2, 3 & 5 bridged, 6 & 2 linked & that's all!
I'd suggest wiring the links as the diagram & then pulling them one by one to see what happens.