Weird electrical problem-headlights - 986 Forum - The Community for Porsche Boxster & Cayman Owners

jhandy · 09-09-2008, 08:45 PM

Any ideas would be great.

The headlights are the problem. Specifically the low beams.
The low beams turn on, like when the car ignition is off, the lights are on, but very dim... Well that is what it is like when the car is on.

Pull the left stalk to you and the high beams flash, BUT push it away, and there are no high beams. The fog lights work.

The parking lights work.... I don't even know where to begin to look. The only thing I can thing of is that the ignition does not recognize the key is in and the car is on, so the low beams don't fully turn on, But that is a guess.

Ideas?

James

Burg Boxster · 09-10-2008, 05:36 AM

slow down, you're asking a lot of questions here... and just to confirm, I presume you do not have litronics - just regular halogens for the lows?

First off, on my '99 at least, the low beams will only come on when the car is running (not just in the on position). Even if the switch is pulled to on, only the 'city' lights will illuminate (it's 5W bulb IIRC in the low beam reflector) w/ the rest of the parking lights (both front & rear). Likewise for the fogs

Same holds true for the high beams - they will only illuminate via pushing the stalk forward when the car is running. The flash, pulling the stalk towards you, works regardless of ignition position.

So... first step to solving the problem is start the car and check them all again. Post back w/ results and we can further isolate if there is an issue w/ a few simple swaps (starting w/ the fuses and then w/ the bulbs themselves since all three - fogs, lows and highs use H7 55W bulbs) and also checking to make sure the plug on the light housing seats correctly.

Let us know what you find

jhandy · 09-10-2008, 09:45 AM

HI,
I have standard lights, not litronics.
I realize that the lights only turn on with the car, But, for instance turn your car on, turn your low beams on, then leave the lights on, but turn off the car.

There still is a very dim light coming from the headlights.

So this is what is going on. With the car on.....turn the switch and there are no low beams, just the parking lights, and a very dim output from the headlights (like when the lights are on and the car is off.

With the car on, and the low beam switch on, there is no High beams when the stalk is pushed forward.

Pulling the stalk makes the highs come on, like your flashing someone.

So that makes me think that the light switch does not recognize that the key is in and the car is on.
I could be wrong, but in any case this is a strange thing.

thanks for helping,
James

Burg Boxster · 09-10-2008, 11:56 AM

The light switch does directly not recognize a key. However, a bad ignition switch can lead to problems w/ lights. Since you are not reporting issues like radio stuck on or key chime continuing after removal let's assume your ignition switch is fine for the moment.

Also, to eliminate the obvious..... when you say on, you not only have the ignition on, but the engine is running correct? On my '99, the lows - fogs and high beams will only illuminate with the engine running. They will not when the ignition is on only. The parking lights will illuminate w/ ignition off or on and w/ or w/o key in ignition. For example - if you had the headlights on and stalled the engine, the lows/fogs/highs would shut off and only the parking and city lights* would remain on. The high beam flash (pulling stalk towards driver also works regardless of ignition position or if there is a key in ignition.

*city light is a small (5W bulb IIRC) located in the low beams housing which can be confused for a dim low beam bulb.

Anyhow, if you motor is running and you're not getting headlights, the problem could be a # of things: bad ignition switch (ruled out per above but not 100%), bad light switch, burnt out bulbs, blown fuses or incorrectly seated headlight housings. Since you get the flash to pass (high beam flash w/ stalk pulled towards driver), let's assume headlight housings are seated correctly, fuses for high beams are fine as are the high beams bulbs.

Now we're down to a couple of things.... light switch, bulbs for fogs & low beams and fuses for each. Easiest to test quickly are the fuses. There is a diagram inside the fuse box so reference yours specifically but generally the fuses are:

Row & # Description
A1 --- High beam right (should be fine since you get flash to pass)
A2 --- High beam Left (should be fine since you get flash to pass)
A7 --- Fog Lights
A9 --- Low beam right
A10 -- Low beam left

Test the lights after swapping and if the issue prevails, you should move on to the bulbs.....

Pull one of the headlight pods (instructions in your manual and tool behind spare tire in tool-kit or you can use a 5mm nutdriver or small socket. Once the headlight pod is out, remove the back cover and swap the hi-beam (we know it works from the flash to pass) w/ either the fog or low beam (they all use the same bulb - H7 / 55W). Incidentally, the placement of the bulbs themselves in the headlight pod is counterintuitive. The low beams are in the upper slot while the high beams are in the lower. Re-insert pod and test low, fog, highs and flash to pass again. If one of them that did not work before now works and the one that did doesn't it's a bulb issue. Go get replacement H7 bulbs (for both sides) and replace all that are needed.

If the issue still prevails, it most likely is the switch itself. It's easy enough to replace - directions and p/n are available using the search function.

Report back your findings....even if they are "opps I didn't have the engine running" as it will help others.

Lil bastard · 09-10-2008, 01:34 PM

I'm still leaning toward the starter (ignition) switch. Not all possible symptoms are always present when one of these fails. Of course, the headlamp switch must also be somewhere on the list of possibilities, but this is pretty easily ruled out using a DMM and checking for continuity at all the various positions. There are no relays for the headlamps, just the foglamps, so not a possibility.

If it were me, I'd start by checking the headlamp switch with a DMM and if that passes, concentrate on the starter switch.

jhandy · 09-10-2008, 06:52 PM

Thanks for the advise, here is the progress....
Fuses ok.
Bulbs look ok, I have no direct way to test them. (filliment looks intact)
Engine on, low beams dont work (both of them), city lights work, high beams only work when pulling stalk, fog lights work.

This just happened, I did not mess with anything, one sec it worked, and the next it did not. (can both bulbs blow at once?)
I will check the switch (stalk) and the light switch (knob) tomorrow.

I am about to give up here soon and just drop it off at the dealer. Nuts and bolts are easy for me, electrical problems have always eluded me for some reason.

I will keep y'all posted.

PS...What is a DMM and where do I get one?

Lil bastard · 09-10-2008, 08:17 PM

Quote:

Originally Posted by jhandy

Thanks for the advise...What is a DMM and where do I get one?

A DMM is a digital multi-meter. These can be had for as little as $10 or more than $200. They have varying features such as voltage (AC/DC), Continuity (a tone or visual signal tells you if there is a proper electrical path or cicuit), Resistance (ohms) and sometimes a temperature probe, Duty cycle, pulse width, memory store/recall, min/max/avg, etc. Of course, the more features, usually the higher the cost.

See: http://en.wikipedia.org/wiki/Multimeter

It's best to get a digital multi-meter because the analog type can damamge some micro-electronics because of the higher voltages they use, also DMMs are usually easier to use (read).

There are many mfrs. of DMMs, with Fluke probably being the best, though Siborg, TPI and Protek are all excellent as well. I have a $10 cheapie which stays in the toolbox and a better Fluke which cost about $60.

You can find them at any lowes, Ace, Menards, Home Depot, etc. as well as many online sources. It's a pretty valuable tool to have for the home, car, stereo, computer, etc.

BTW, you can also use a DMM to check a bulb or fuse using the continuity feature.

jhandy · 09-19-2008, 09:57 AM

Well the problem was the light switch. When rotating it to turn the lights the connection to turn on the lights would not connect and the car thought that only the parking lights where on.
New switch and no more worries.

Thanks to all for the help-you guys saved me money once again.

Wret · 11-04-2008, 05:24 AM

I'm having the exact same problem. Did you replace the switch yourself? I'm wondering how difficult this is.

koit · 11-25-2008, 01:50 PM

I'm also getting a no low beams issue. Both lamps.

How easy is it to replace light switch, is it a dealer scenario !?

jhandy · 11-26-2008, 05:27 AM

Replacing it is easy as long as you are double jointed and a skinny fellow. You have to reach behind the dash to the backside of the switch and there is a nut, this hold on the switch. Then just unplug and plug in a new one.
The switches are not expensive and can be bought from eBay for about 15$.

jhandy · 11-26-2008, 05:34 AM

The removal guide I used is here:

http://www.renntech.org/forums/index.php?showtopic=3131

koit · 11-26-2008, 08:13 AM

Thanks for the info.

I took it in to an auto electrician today and indeed it was the lamps. Both blown......
Seems that it is an inherent porsche scenario that both do go together.

At least it's fixed !

Burg Boxster · 11-26-2008, 12:56 PM

Quote:

Originally Posted by koit

Thanks for the info.

I took it in to an auto electrician today and indeed it was the lamps. Both blown......
Seems that it is an inherent porsche scenario that both do go together.

At least it's fixed !

It's not just a Porsche scenario. Think about it for a moment...

- the lamps/bulbs were most likely made around the same time
- they were installed in vehicle at same time
- they run at the same time

Whenever I replace bulbs, especially headlight and brake light bulbs, I just do the pair at the same time. Although they don't usually go bad at the exact same time, I find I'm more often than not replacing the opposite side w/in a week or 2. Having said that, I suspect one side went out and you didn't really notice it until the other side also blew.

In a pinch, if you don't have the litronics, the high,low, and fogs all use H7 bulbs and can easily be replaced yourself. So easy in fact Porsche even gives you directions on how to in the manual as opposed to "See you Authorized Dealer" B.S.

Lil bastard · 11-26-2008, 02:11 PM

Quote:

Originally Posted by Burg Boxster

It's not just a Porsche scenario. Think about it for a moment...

- the lamps/bulbs were most likely made around the same time
- they were installed in vehicle at same time
- they run at the same time

Whenever I replace bulbs, especially headlight and brake light bulbs, I just do the pair at the same time. Although they don't usually go bad at the exact same time, I find I'm more often than not replacing the opposite side w/in a week or 2. ...

Yup!! In addition to both bulbs being in service the same amount of time, as a bulb ages it's resistance increases. This is OK because both bulbs on the same circuit are doing this at the same rate.

But, if you replace only a single bulb in the circuit, this new, fresh bulb has much less resistance and so passes more current to it's opposite causing it, in an already 'depleted' state, to 'work' harder and so the second original bulb blows more easily/quickly.