Cass944

my passenger side headlight has been weird lately. for the last week or so if i turned on my brights my passenger side headlight would turn off. so i just figured that part of the bulb had gone bad or something. then suddenly last night the bulb totaly went out.

I put one of my replacement bulbs in today and I also changed the fuse which was blown. instead of just working perfectly it had to do the normal porsche thing and only be kinda fixed. the light turns on but its exteamly dim. and when i turn on the brights it turns off. but the drivers side light works fine. i took a voltage reading from the middle connector of the socket on the lights to the ground connector and i get 10.83 volts then with the brights on i get 10.90 volts form the same connector. isnt the voltage supposed to come form the 3rd connector in the socket when the brights are on? either way i think its a ground issue somewere. were should i look for a bad ground? im not sure were the headlight is grounded.

89magic98

Is there an intermittent connection in the harness where it folds/bends where the light goes up and down? That was the cause of my passenger side headlight failure.

Cass944

i remember seeing that but didnt think to check it until now. ill go look. thanks

89magic98

A broken connection will not be visible from the outside. There are several wires inside another rubber harness. You would have to cut open the rubber harness in order to "see" the break. But you could try squeezing/pulling/pushing on the harness and see if the light turns on and off, or gets brighter or dimmer.

Cass944

ok i take back that 10 volts thing. i retested.

i took a reading from the second plug (the one stuck to the back of the headlight assembly.

passenger side is between 3 and 4 volts and the drivers side is 11.5 volts solid. the wires around the headlight are ok. i tested the little span that goes from the connector at the back of the assebly to the bulb itself and its fine. so its somewere up in there... great.

Cass944

anyone got a wiring diagram?

do the 2 seprate power lines to the 2 headlights both have theyre own line from the fuse box? or is it one line going out then it splits into the 2 lights? i tried moving the wires around. i want to cut open some of the rubber insulation and check the voltage on the wire by the fuse box but both headlights have yellow power wires.

Cass944

yep still stumped....

I did notice something though. when i turn on the lights. the one that is dim slooooowly comes on.

anyone?

So Cal 89 944

I have the same problem you do but it,s my driver side lite.
I've narrowed it down to a bad ground. Only problem is I'm recovering from back surgery.

According to my Haynes manual.
Both headlites have 2 power feeds for each headlite(1 low beam 1 high beam)fed straight from the fuse to the headlites. Total 4 fuses 2 low beam 7.5 amp and
2 high beam 7.5 amp. Both have 1 connector between headlite (actually 2 if you count the back of the lamp) and fuse.
Each headlite has its own body ground with no connector between lite and frame. Ground is mounted on drivers frame rail just behind headlite bucket, 2 large brown wires.
My small problem is the ground wire coming out of the hradlite pigtail is smaller than the one on the frame rail. Which makes me think that there is a connection in the harness.
My big problem is I can't bend over to fix it.

Hope this helps Jeff

Cass944

i installed a 100w fog light kit iceshark sold me and i had to put a big #10 wire to the place were the headlight grounds. the light worked fine for a day or so though... so thats why i dont think its that. but maybe ill have to mess with that ground again. the drivers side one is really hard to get to. you would think it would be easier seeing as how you dont have the washer fluid rez and the headlight motor but nah the drivers side is a pain.

anyway i found a post from not to long ago using the search and it seems to be ground related... im gonna try using the ground from my drivers side and the power from my passenger side and see what happens. that way i knwo for sure its the ground i suppose.

also. there is a feed for the high beam and a feed for the low beam. the thing is that i only get power from one of them. If i put a volt meter on the low beam connector and turn the lights on i get like 3.5 volts. if i turn on the high beams without moving the meter that line jumps to about 4.5 volts. if i test the high beam feed with the voltmeter while the brights are on i get 0.... i didnt check the drivers side yet but that seems really weird ey?

So Cal 89 944

Definately sounds like a ground problem though mine did the same thing until I charged the battery. I then grounded my probe to a good bare metal ground and read 11.5V/11.2V voltage across the terminals. Then did a continuity check on my ground and Voila! OL: OPEN LINE.
Fixing the ground is easy just clip your brown wire add connector ansd screw it down to fresh metal.
I'm a little **** I want to find the original connection and fix it.
Hey when you figure your's out how bout swinging over to sunny So Cal and fixing mine. Dude I can supervise. LOL.

Jeff

Cass944

hehhe yeah i just got it. I took my tester and put the pos on the ground of the bulb then the neg on some nice bare metal on the frame and bam instant bright light. so i busted out with some of the leftover 10 guage wire i had from iceshark and made a new ground completely out of that for the light. and im gonna do the same for the other side. to bad my battery is completely dead now. i cant even make the lights go up or down under its own power now.... danget.

Redlyne_mr2

Sorry for the late response I could have helped you earlier. This is a common problem due to a bad ground as you found out. Stupid single dim headlight looks so ghetto