930 /911 headlight quick help, question?

look 171 · 07-30-2022, 08:13 PM

Driver side head light is completely out for months now. Headlights do not get used often only once in a blue moon, in summer evenings. Just after dinner, I decided to removed the steering wheel but can't get the big nut out without a large enough socket because the high /low beam switch stays on high beam all times. Luckily it was fixed by bending the tab inside. My question is if head light bulb is burned out, should the high beam work but not low beam? One fulfillment should only be burned not likely both? Thought? I hate getting the headlight out because I can never seem to get the trim ring back on correctly. It shouldn't be the switch because the other light works fine.

Noah930 · Noah930's Garage

There are two filaments in the bulb.

pwd72s · 07-30-2022, 08:26 PM

What year 911? Pick of the light might help...some use 2 filament bulbs, some use 2 separate bulbs, some are sealed beam, etc. Do you have a multimeter? This would involve taking the bulbs or bulb out, and testing to see if you get 12 volts to the contacts on high & low beams. 27mm socket should fit the big steering wheel nut, unless Porsche changed the size since 1972. Could be the switch, could be a fuse, could be burnt wiring. Mark wheel position before pulling the wheel...

look 171 · 07-30-2022, 08:27 PM

H4. I figure it has two filaments. 88 930. Got rid of the H5s.

look 171 · 07-30-2022, 08:28 PM

Quote:

Originally Posted by pwd72s

What year 911? Pick of the light might help...some use 2 filament bulbs, some use 2 separate bulbs, some are sealed beam, etc. Do you have a multimeter? This would involve taking the bulbs or bulb out, and testing to see if you get 12 volts to the contacts on high & low beams. 27mm socket should fit the big steering wheel nut, unless Porsche changed the size since 1972. Could be the switch, could be a fuse, could be burnt wiring. Mark wheel position before pulling the wheel...

If burned fuse, should both lights be out? Looks like I wouldn't finish this evening without a 27 mm socket.

pwd72s · 07-30-2022, 08:30 PM

If my memory serves, and it may not...there was a fuse for each...high and low beams.

pwd72s · 07-30-2022, 08:31 PM

Might try to move this to the tech side? We're on off topic...

(edit) On my memory...my 911 left here well over a decade ago...so don't take it as gospel

look 171 · 07-30-2022, 08:42 PM

Ok, thanks guys

masraum · 07-31-2022, 06:42 AM

Quote:

Originally Posted by look 171

Driver side head light is completely out for months now. Headlights do not get used often only once in a blue moon, in summer evenings. Just after dinner, I decided to removed the steering wheel but can't get the big nut out without a large enough socket because the high /low beam switch stays on high beam all times. Luckily it was fixed by bending the tab inside. My question is if head light bulb is burned out, should the high beam work but not low beam? One fulfillment should only be burned not likely both? Thought? I hate getting the headlight out because I can never seem to get the trim ring back on correctly. It shouldn't be the switch because the other light works fine.

Quote:

Originally Posted by Noah930

There are two filaments in the bulb.

High beams and low beams are separate filaments for sure. When the high beams are on, only that filament burns, I'm about 95%.

On the older cars like yours, the stock headlight setup does NOT have a relay for the lights, so all of the current goes through the switch and the highbeam switch in the steering column. Over time, that switch gets hot and will frequently do what you're describing, get to where it's all high beam all of the time. Or in my case with my old '88, I'd hit a bump or something, and it would switch to high beam. I did the same with mine, bent the tab in the switch and that fixed the problem temporarily. (I ended up selling the car before it became an issue again).

The real fix is to install a relay into the system so that the high beam switch only has the relay activation current going through it instead of the full current of the lights.

masraum · 06:51 AM

There was even a guy on the 911 tech board that used to put together and sell a "relay kit" just for the headlights, but that was probably >15 years ago so there may be a new solution, but chances are that guy is not still around.

high beams turning on themselves

turn signal switch quick fix pictures

Erratic high-beams - very easy repair

I didn't read through ^those^ threads, so I don't know if what's suggested is correct. I think the first one is actually a thread that Shaun started. One of them is many pages deep. I assume since it's such a common issue, that they all end up at the same point. The 911 tech board was always a great source of correct/accurate info in the past. I would assume that hasn't changed.

rusnak · 07-31-2022, 08:15 AM

Yup, 2 filaments in each bulb. I think checking fuses is your logical starting point.

To get the trim ring back on, use a metal ice pick or a thin punch or awl, like a spring loaded center punch to line up the bolt hole with the threaded tab BEFORE attempting to turn the base screw to bolt the headlight bucket back on. Then the trim ring can be centered using the same ice pick or punch.

Noah930 · Noah930's Garage

Jeff, there are separate fuses, as well. One fuse for regular/dipped beam, one for high beam. (And obviously for left and for right, so a total of 4 fuses for the front headlights.)

pwd72s · 07-31-2022, 03:50 PM

Quote:

Originally Posted by Noah930

Jeff, there are separate fuses, as well. One fuse for regular/dipped beam, one for high beam. (And obviously for left and for right, so a total of 4 fuses for the front headlights.)

So...my geriatric memory isn't all gone.