headlights on and lights just go up and down and turn ignition on

Texas944 · 12-09-2007, 07:19 AM

SoCal this might be a good one for you - with the key out of the ignition, turn the headlights on and everything comes on like it would if you turned the key on (alt warning light, radio, fans, etc) - and - the headlights just open and close open and close open and close (wont stay open). To drive it one night i had to pull the relay on the light motor and then wind them up by hand. I did replace the relay on the side of the headlight motor and no change. the battery is also being sucked dry of power.

please help?

jmd_forest · 12-09-2007, 08:58 AM

Pull the headlight motor. Pull off the plastic covers and relays and look for the small circuit board controlling the switching. There should be 2 diodes on the board (they look like resistors but usually have a single stripe indicating the direction that current can flow). Go to your local electronics store and buy 2 diodes about the same size. (Shouldn't be more than 25 cents or so each. Take the motor or diodes with you. The guys at the electronic store should be able to provide a reasonable match. The match doesn't have to be perfect) Clip out the old diodes and solder in the new ones making sure to match the striped end of the new diode with the cooresponding striped end of the old diode. It worked for me.

Texas944 · 12-09-2007, 10:23 AM

do you think i could be getting feedback thru those diodes that would be causing power to come on everywhere else when the headlights are turned on? i hope it is going to be a simple fix - fingers crossed.

Texas944 · 12-09-2007, 10:47 AM

UPDATE - i changed out the headlight motor for one i had on the shelf and still the same thing - turn the headlights on and the headlights go up and stay up (and the radio, etc also go on).....turn the headlights off and everything goes off except then the headlight motor stays on and of course the lights just keep going up and down.
does this give anyone a better idea of what to look for? thanks.

jmd_forest · 12-09-2007, 02:05 PM

Well, If you changed out the headlight motor it certainly is not the diode circuit as I mentioned earlier. I has very similar symptoms in my 924 and I tracked it down to the diodes. Sorry it didn't work out for you. Looks like you'll be spending some time with a DVM in the near future.

jmd_forest

Aufenbahn · 12-09-2007, 07:04 PM

When my headlights were doing their up and down dance it was a bad ground wire under the fuse box.

juVius · 12-09-2007, 10:43 PM

have you tried another switch?

Texas944 · 01-07-2008, 05:15 AM

FIXED......after pulling the rest of my hair out (and after changing the switch, too), I decided to let the lights do their winking thing and started pulling fuses - the #2 fuse killed them which is the fuse for the G16 relay which is for the headlight washing system. Pulled the relay out - problem solved!
Thank you for all of your suggestions. Hopefully if this happens to anyone else it wont take as long to diagnose like it did me!
Cheers,
Brett.

juVius · 05:24 AM

that's good to hear brett... hopefully your hair grows back soon..... lol... porsche should market a hair growing tonic for problems like these...

SteviePorsche · 07-24-2018, 09:00 PM

Quote:

Originally Posted by Texas944

FIXED......after pulling the rest of my hair out (and after changing the switch, too), I decided to let the lights do their winking thing and started pulling fuses - the #2 fuse killed them which is the fuse for the G16 relay which is for the headlight washing system. Pulled the relay out - problem solved!
Thank you for all of your suggestions. Hopefully if this happens to anyone else it wont take as long to diagnose like it did me!
Cheers,
Brett.

Ha. Thanks for this one! 10 years later and I have same issue on 90 944 s2. My eyelids started winking today with car off and key out so I put them up and pulled relay off headlight motor. Then started digging on forums

. Pulled G15 and G16.- gong thingy. Put headlight motor relay back in headlamp motor and all is well. still cautiously optimistic that this is resolved. Lights go up and down and on and off again as they have done for past five years now flawlessly. Fingers crossed

944 S2 · 07-25-2018, 06:09 PM

So in conclusion is this a relay issue? Did new relays fix this issue?
Occasionally my headlight light as possessed and go up and down on their own!

SteviePorsche · 09-23-2018, 08:51 PM

Quote:

Originally Posted by 944 S2

So in conclusion is this a relay issue? Did new relays fix this issue?
Occasionally my headlight light as possessed and go up and down on their own!

I dont know for sure. I dont have headlight washers so I guess I dont meed it at all. i just took relay out and threw it in the drawer. All is still good so far. G15 == useless??

SteviePorsche · 09-23-2018, 08:56 PM

Quote:

Originally Posted by SteviePorsche

I dont know for sure. I dont have headlight washers so I guess I dont meed it at all. i just took relay out and threw it in the drawer. All is still good so far. G15 == useless??

I did put new relays on headlamp motor circuit in the fuse box and also directly on the motor with no luck initially, so just put the old ones of those back on too. Now I have a couple extra good ones. If I plug that G15 back in the headlights take off again whirling about.

Anybody know if it runs some other crazy thing in the car like glovebox light too? It appears I just dont need it