Headlamps staying up

[John Sims]

Significant embarrassment. [&o] On returning from Porsche Club this evening I turned off Beaky's headlamps and they stayed up [].

Have checked fuse 2 and it looks OK. It is 25 amp so would be pretty obvious if it had gone.

Have checked the motor connections and they look OK but haven't had a chance to put a tester on them.

Have pulled the relay on the motor and will replace as I'm hoping it is this which will have gone - again not tested the battery in my multimeter is flat []. If I had a wire with spade connections on either end which terminals should I plug in to and would the connection only be periodic switched off by the position of the motor?

As the headlamp motor must only receive a periodic supply to lift or drop is there a further switch control box some where or what else could it be?

 

[Fen]

I'm not sure it's a periodic supply. I know the motor kicks in and grabs the lights from you if you manually try to raise them with the knob on the motor when they are off and the battery is connected. Perhaps there is a microswitch that tells the relay to lower them I guess, but if there is that could be your problem.

 

[John Sims]

Have ordered a new relay from my OPC at £26 [] so I hope it is that.

Looking at the Haynes manual (so not much of a recommendation) it would seem that there might be two contacts on a cam follower so this will tell the circuit what position the lights are in.

I do recall that previously when I turned the lights off there was a hesitance before the pods went down .This being the case I am a bit concerned that this might be a burnt connection on these followers, if that is what they are.

 

[skendrick]

My headlamps started to play up recently and I found that the bracket to the washer bottle had broken and was pressing on the connections stopping it working. Quick DIY job on the bracket and all is working, worth a look.

 

[John Sims]

While I seem to be having this conversation with myself [] I shall continue as more becomes apparent.

I took the casing off my original relay and cleaned the contacts.

I then installed the relay without the casing and turned the light switch on and off. Lights came on and stayed up.

By flicking the relay across by hand I can make the lights go down and if I hold the relay closed they go up and down to their hearts content.

If I hold the relay closed to put the lights down (with the lights off) and then turn the lights on (not holding the relay) the relay clicks across and the lights go up to their correct position......Buttocks! Nothing wrong with the relay then [].

So, I deduce, the fault must be with what ever switching tells the lights to go down.

Any ideas so far?

 

[Fen]

On reading your description I was thinking "good, it's the relay then" as I had assumed it was sticking or had a broken spring or something. Doesn't it just spring back when the power through the lighting circuit goes off?

 

[John Sims]

ORIGINAL: Fen

On reading your description I was thinking "good, it's the relay then" as I had assumed it was sticking or had a broken spring or something. Doesn't it just spring back when the power through the lighting circuit goes off?

The relay is purely a relay, it is switching a higher power supply with a lower power supply. If I keep the relay closed manually the motor continues to turn and the headlamps go up and down and up and down. Amusing for a couple of rotations but the novelty quickly goes away.

What seems to be missing is the switch signal to drop the lights, the lifting seems fine.

 

[morris944s2john]

Maybe the rotary headlamp switch is faulty??

 

[944Turbo]

A short somewhere? in the flexing cables on the rear of the brackets maybe?
Tony

 

[John Sims]

ORIGINAL: morris944s2john

Maybe the rotary headlamp switch is faulty??

I wondered that myself.

ORIGINAL: 944Turbo

A short somewhere? in the flexing cables on the rear of the brackets maybe?
Tony

I'm not sure about that as the headlamp illumination seems to be independant of the lifting and dropping.


Any road up, the £27 relay arrived this morning (complete with VW markings and 10 amp rating compared with 30 amp of the original). As I suspected it didn't make a blind bit of difference. [] [:'(][]

There are 4 wires in the plug to the headlamp motor. 2 are obviously thicker than the others so I am assuming the thick wires are a constant power supply and the two thinner guage wires are the switch lines.

I know that I have power, as I can opperate the motor by manualy closing the relay, but I don't yet understand the switch lines. Are they two seperate lives which use the power supply earth, or are they live and earth?

And I still don't undertsand how the headlamp motor knows when to switch on to come down.

"On" is easy (I think). You switch on the headlamps and a switch current goes to the relay and the motor opperates until the motor microswitch interups the signal when the headlamp is up.

Down must be a seperate constant live which is interupted by a motor microswitch when the headlamp is down or when the headlamps are turned on (so a flick over switch) - this would account for Fens comments that if you try to lift the headlamps manualy when switched off the motor pulls them back down again.

This all being the case either:-
a) The headlamp is down microswitch (in the motor) is damaged and constantly open.
b) The headlamp down constant live wire is damaged
c) The headlamp switch terminal for the constant down supply is burnt and not sending the signal.

So....If I get a "live" from one of the switch wires when the headlamp is down this means the wire and the switch is OK and it is a faulty motor microswitch. [8|] Now where did I put my spare multi meter? []

 

[944Turbo]

Never played with the headlight mech. before so this is interesting.
Microswitch would be my next guess as the flexing wires are eliminated, is there a gearbox off the motor with it hiding inside?
Is there a second relay - under the dash or in the fusebox I wonder?
At least with your new relay being the wrong rating you have a V good excuse to return it.
Tony

 

[John Sims]

As my late departed Grandfather used to say

"If all else fails, read the instructions"

I don't know. I call upon the intellectual might of the PCGB 944 Forum with comments, suppositions and intelligent speculation and nobody says " Have you tried fuse 16" [][]

 

[Fen]

Just a thought, John. Have you tried fuse 16?

 

[Guest]

Just to repeat-Mind your fingers in there, as mentioned earlier, even with things switched off the pods have a way of going full swing if you push them manually, and with considerably more force than you would think necessary!
I had the reverse problem as mine wouldn`t go up-so to speak. Bought a second hand motor-top relay from ??? who had one from his S2, and everything worked fine again.
All of which is no help to John, but do mind your fingers.

 

[944Turbo]

Well we know now, thanks for all the info John, you are now the register lighting specialist..... Congratulations,[]

Tony

 

[John Sims]

ORIGINAL: 944Turbo

Well we know now, thanks for all the info John, you are now the register lighting specialist..... Congratulations,[]

Tony

I'm glad that my pain has been your gain []

It has been quite interesting though (now that we have worked it all out) and all makes sense - in a complicated Porsche way.

 

[Fen]

Is that they Royal "we"? I think you did it yourself with us (virtually) standing around with a beer making smart comments.

 

[John Sims]

Ah but, it was the smart comments that clinched it with "the headlamp pulls itself down again" clue being the the critical piece to the jigsaw. []