Headlamp leveling motor operation

[tref]

Can some-one give me an overview of how these work (a little more than twiddle the switch in the car and the headlamps go up or down[])?

I know both the motors on my car work, as I can hear them make a nasty noise, how-ever, the headlamps don't move. Having taken the covers off the headlight pods the lights are bodged together with all sorts of tiegrips, washers and jubilee clips. I'd like to get it all back as it should be, but would like to understand how the motors on the headlights know where they are for example?

Tref.

 

[chrisg]

Tref,

Unlike previous posts on here, I'm going to have to have an educated... guess, as the headlight side of things is not one area of 944's I know intimately well, unlike the drivetrain, suspension engine etc.

My understanding (carefully worded here..) is that there is one motor on the drivers side that moves the lights up and down. As has been expanded on many times here and other forums, this motor and the gearing are very strong and torquey and are designed to put the lights up and down at significant speed with pressure on the lights...

Again, my understanding is that the one motor drives the lights up and down, but the two movements are controlled by separate systems/ circuits. The motor also (in typical German overengineering fashion) has a manual override facility with the knob on the top that will pop the lights up and down should the fuses/relays/circuits go.

To date I've yet to have any motor related issues, but lights wise I've had the classic 944 broken wire internally to the lights where it flexes and then keeps blowing bulbs/ fuses - soldering and heat shrink....

One other thing to bear in mind, whilst I'm dishing out pearls of wisdom..... If you have an early (I think pre 88 car) that you do the 'stealth' running modification on which the later cars already have, ie sidelights on but pods down., If you have the indicator stalk on full beam the lights won't pop up !!!!

I learnt this the other weekend prior to visiting the Ring - nearly shit myself before I worked out what was going on !

 

[tref]

Thanls Chris,

I believe you are refering to the headlight "pod" raising and lowering, and your understanding is pretty much spot on. Unfortunately, what I am refering to (and I should have made it more clear, my fault) is what I refer to as the "leveling mechanism".
On each "Pod" there is a seperate motor, a couple of inches length and diameter I would guess, teh shaft of which I believe to be connected to the bottom headlight adjuster - controlling the "up and down" adjustment of the headlight aim. The connector to these motors have three wires each as far as I can see. So I presume two of these are connected to the motor, the other presumably is feedback of position?
I would like to know so I can disconnect teh connector, and "hot-wire" the motor, so I can check it is indeed working as it should be, or if it is seized and just "humming" a lot. How-ever, I don't want to cause damage if I don't have the end of travel feedback in place or similar.

 

[BlackMagic]

Hi,

This is an area that I have more experience in that I like to remember. 3 smashed headlights in 12 months!

Inside the pods the headlights are first mounted on a plastic plate that is then screwed to the metal of the pod. The plastic plates are cheap(ish) (£15 each) and still available from Porsche; and having tried to reuse old mounting plates I wouldn't do it again.

The plates arrive with the hole for the electric adjustment containing a filler and manual adjustment screw - This was great for me as one of my motors had seized and as I hadn't adjusted the height of the headligts (except to see if they worked) in 20 years, replacing the electrics didn't seem worth it.

Back to the job......

• Headlights up
• Remove the connector from the headligh lift motor to top them going back down at an inopportune moment!
• Take all the plastic bezels etc. off
• Undo the 4 screws that hold the plastic plate to the pod
• If you move it a little bit forward and turn it a little anticlockwise (looking from the front) you can just release the hight adjusting motor from the back. It has a bayonet fitting.
• If you don't do it this way you have to dissassemble a lot more of the headlight mechanism to get the motor out
• Its now easy to remove all the bits
  
• Then as they say......reverse steps 1 to 4
  
  However....... the real trick is getting the headlamp bowl back onto the mounting plate. I have heard several approaches but the one that seems to work is as follows:
  
• Refit the adjustment motor to the mounting plate. Note that this is a real fiddle!**** as again you need to use the small amount of rotation available to get the bayonet on the motor back into place
• Screw the mounting plate back into the pod
• Put the 3 plastic mounting sockets (called articulated pieces 944 631 912 00 in the parts book) into the metal mounting brackets on the edge of the headlamp bowl
• Give each fitting a liberal coating of copperslip
• Have a strong drink, smoke, or what ever gives you confidence
• Push firmly and evenly on each mount in turn
• and ...in the end, just when it seems like you will break it....click and it locks in

One final hint

Get some spare articulating pieces. They are only 30p and I've broken a few putting the headlights back on which is very annoying on a Saturday afternoon as nothing else will do.

Also, if you are very lucky it may just be the articulating pieces that have broken and then you won't need to mess aroung with getting the mounting plates out.

Good luck

William

 

[chrisg]

There you go ! A brilliant in-depth explantion from a man who knows the job concerned, nice write-up !

 

[tref]

Indeed, excellent... Paul, is this one that should be added to the FAQ or technical section? What I might do is see if can take some photos... the only thing is as far as I can see the plastic mounts are fine, it is just the little white plastic clips (articulated pieces?).

 

[bmnelsc]

Thank you very much for the post. I'm in Canada with a 91 944 S2 RoW car and no one has experience with this system as it was not provided on North American models. I've hanged my headlights from left hand traffic to right hand traffic using a similar procedure as you described. My articulates were brittle so I broke them off and used new ones. I didn't remove the motor from the retaining frame as it looked like a lot of disassembly would be required and the motor would have to be back in place before the headlight could be mounted. I used a 1x1x20 cm stick of hardwood to push the articulates over the stud heads though (I'm old and don't have the hand strength I used to. Using the piece of wood allowed me to push with my thigh while firmly backing up the retaining frame with my hands as I was afraid of breakage.

Some additional questions please.

1. On the retaining frame, the top left stud has a knurled shaft and no "screw head" to support adjustment. Does this shaft actually turn in the retaining frame for coarse adjustments or is it fixed in place?

2. On one headlight, the lower threaded stud that attaches to the leveling motor is screwed in all the way - on the other headlight, the screw can be turned in or out. Are these studs integrated with the motor or are they removable?
The parts book for these show only two threaded adjusters per pair of headlights and show the leveling motors with the adjusters assembled.

3. You mention using new retaining frames each time as reusing old plates was a problem. Can you elaborate please? Maybe I was lucky as only one stud had any corrosion on the ball end and a little steel wool cleaned it up very well.

Finally - a moan about how Porsche abuses us. You say articulates are about 30p each - when I special ordered they cost me $4.71 Canadian each. 6 articulates and 2 headlights set me back approx $450 Canadian. As you can imagine, I don't want to have to buy retaining frames also.

Thanks again for the excellent write-up.

Bruce Nelson
Edmonton, AB, Canada
bmnelsc@telus.net

 

[Hilux]

Remove the fuse or disconnect the battery if working on or near the headlights.

If you knock the manual reset on the motor end or short some wires its bye bye fingers.

 

[berg944]

If you can not get them to work mail me, I have a complete set of adjustable lamps in the loft.

Mike

 

[bmnelsc]

Hilux - thanks - good advice for those of us that cut corners...

Mike - thank you - I'm going to keep trying for a while. Just in case...would you be willing to seperate the headlights from frames and motors?

In Canada we have left hand drive (right hand traffic) so the headlights would not be useful to me. On the otherhand, I have a pair of left hand traffic headlights that I can't use

 

[berg944]

I could give it a go!

I would imagine the postage would be silly.

6 articulates and 2 headlights set me back approx $450 Canadian.

You could have used VW Beetle lamps if you swap the frames. The frames fit but you can not get the lids on. The only difference is the hole for a side light. I just blanked it with a rubber bung.............£18 ea.

Mike