1st Post: Headlight Headache

unrealworld82 · 03-14-2011, 09:17 PM

Hello, I am new to this forum. It looks like one of the best on the net, pleased to meet you all.

What really brought me here is my need for some help with troubleshooting a problem with my 1986 944 NA. The problem that I am having is that the headlights are not working. The brights will light up when I hold the lever back toward the steering wheel. Other than that, nothing. No dims, no brights. I have tried no fewer than 3 (including a $200 new one) and they all do the same thing. My mechanic has tested connections throughout the signal flow and they are all good up to the point of the switch. Any ideas? Could it be a fuse box or relay somewhere?

A second problem with lighting is that the rear left tail light/blinker is just staying solid... not flashing.

Any help is MUCH appreciated, both me and my mechanic are just about ready to drive it over a cliff.

Rasta Monsta · Rasta Monsta's Garage

Perhaps there will be a better mechanic at the bottom of the cliff.

Sounds like a relay to me. Where are you located? Have you considered buying a repair manual?

unrealworld82 · 03-14-2011, 10:28 PM

Thanks, hah. I think.

I, of course could get the repair manual but I thought the Hayne's one is crap???

Any recommendations for a better one?

Oh and I'm in Georgia, USA

Rasta Monsta · Rasta Monsta's Garage

Haynes is better than nothing. You can also find a pretty extensive list of procedures over at Clark's Garage:

Clark's Garage Shop Manual Index

petrolhead611 · 03-15-2011, 02:45 AM

Hi, had the same headlight problem as you months ago. I changed the rocker switch on the dash-problem solved. Then, a few weeks later, on the way to the annual inspection no less, same problem occurred as I was going through a tunnel. I had recently disturbed the connection to the headlight motor in order to remove the screen wash bottle, so once out of the tunnel I wiggled that connection and,hey presto, passed inspection.

SolReaver · 03-15-2011, 08:51 AM

Trust it from a man who has had so many headlight issues...I nicknamed my car "blinky".

1) check for burnt headlights. (don't laugh it gets a lot of folks)
2) connections AND grounds. same as above
3) the headlight switch itself (designed by a demented watchmaker)
4) the wiring going to and from the headlights. Check for disconnects and or shorts.

The current flow diagrams at this site are good enough to get you through it. spend some quality time with your car and a good multimeter. Clarks is a good resource.

WARNING: these cars bite! Literally! you can chop a finger (or two) if you are not careful. so be careful. Disconnect the battery any time your hands linger near the baskets.

bp2930 · 03-15-2011, 02:46 PM

eBay has manuals on cd that are a lot better than Manuals you get at your local auto part store

massive · 03-15-2011, 03:35 PM

Check out my overhaul procedure here 944 Foot To The Floor: How To Troubleshoot Porsche 944 Headlight Problem

unrealworld82 · 03-15-2011, 09:12 PM

Thank so very much for the replies so far. A lot of great information. I am going to work on this issue thoroughly Friday and will report back my findings.

Really, I'm already loving this forum!

Laptop_geek · Laptop_geek's Garage

Quote:

Originally Posted by bp2930

eBay has manuals on cd that are a lot better than Manuals you get at your local auto part store

They are here too, for free.

Documents - Porsche 951 - texasblake.com-

unrealworld82 · 03-21-2011, 12:05 PM

Still looking at it and still no luck. My battery keeps dying now. Seems like a ghost in the electrical.

SolReaver · 03-21-2011, 12:57 PM

No worries...At least for me that is... Disconnect the battery negative post when not in use (duh) and see it the battery holds a charge all by its lonesome. Better yet test the darn thing.

OK, once the battery is "Known good" with the car off... determine what circuit (fuse) the current / voltage / amperage / juice is draining through. I THINK you can put a test light in line from the negative to the ground. Light on...something is using power. I go fuse by fuse. it is a good excuse to clean all the fuses and contacts.

It kinda stinks to do the work...but a man's gotta do what a man's gotta do...

Oh, and the clock and radio sometimes draw just a little power constantly so rule them out first. Hatch light? Interior light? Glove box light? Hood light?

unrealworld82 · 03-21-2011, 07:12 PM

Ok, so forgive me for being a newb.

I am trying to figure out if the signal for the lights themselves (the electricity that turns them on/bright/dim) actually passes through the headlight motor? What are the four pins on the molex type connector that go into the motor for? What does the relay there control, the lights or the motors, or both? Could shot motor cause the lamps not to work? (But the motion of the lights is fine).

unrealworld82 · 03-22-2011, 08:01 AM

Someone also told me that this could have something to do with the ignition switch? What do you all think about that?

SolReaver · 03-22-2011, 08:51 AM

I can absolve you of your ignorance....
Dominae Spiritus Sancti....Absolvo Idiotes....There done!

I however cannot absolve you of the minor sin of "sloth" nicely put. You have to follow the wiring diagrams. It is your car and this is why mechanics make money, it is work. The Headlight switch and hi low switch carry a goodly amount of current and therefore are prone to burning out. In an ideal world...the switch would feed headlight relays. It doesn't IIRC, unless you add them yourself. (a little wiring....a little splicing...)

here, see for yourself.
http://www.pelicanparts.com/944/electrical/944_84_2_1.jpg
Task to redeem your Porsche: go through the current flow diagrams and "pin out" your headlight switch ad hi /lo to see if it has gone bad. it IS possible the hi / lo stalk switch may be bad. The prob as you described i would check hi lo first.

FWIW, when I have motor probs the headlights go on and the hi low operates fine. This doesn't do me much good with the headlights retracted.

If it turns out to be bad headlight connectors or burnt lanterns.....(did you check?) then the car is just screwing with you. They all do that.

Don't chop your fingers!

unrealworld82 · 03-22-2011, 08:27 PM

Thank you, for the lecture. I am willing to do any of this work, I just have very little time for goose chasing, as I have been so far. I should add that I have tried no fewer than 3 combination switches and 2 headlight (dash) switches. All with same result. Have used a test light to check practically all connections, fuses, etc. Everything seems good. Yet, no headlights. I get brights if I hold the stalk in the "bright" side while driving. That suggests it is not the lanterns, right? Thanks.

Rasta Monsta · Rasta Monsta's Garage

Somebody's getting a bit brittle!

unrealworld82 · 03-22-2011, 10:23 PM

LOL, me or him? Sorry, I'm not trying to be a dumb dumb... just trying some new stuff with the car. Thanks to all.

SolReaver · 03-23-2011, 11:55 AM

Heh, Rastas prob talking about me...I can be a bit abrasive around the edges. Of course with Rasta...ya never know. If I come across a bit sarcastic or heavy handed don't take it personal. once ya get to know me you will understand. I have all the patience and tact of a drill sergeant.

Okey dokey... I will see if I can "essplain it to ya Lucy"
First...Do ya get voltage to the low beam connector on the lamp/ lantern/ headlight? also, is there a good Ground connection?

if no, you have to find out why. Using the current flow diagrams referenced...you need to check for voltage at key points. Is there power coming out of the switch? into the switch? from the fuse to and or from the switch?

Yassee...I don't know what is wrong...I am guessing from many miles away and that makes it difficult as my crystal ball is out of batteries. The logical and time effective way to accomplish your objective is to find out where the power is...what path it should take... and find out why it isn't getting there. Think of it as a path that the power SHOULD be going down, but isn't.

So far all I know is that "it doesnt work" and "replacing parts didnt fix it". We need a more logical and organized approach as time is a precious gift not to be squandered. Therefore, get down and dirty...Check for hot at the test points for the basic circuit. Work your way back from the light or forward from the battery. IMHO, back from the light is a better choice. If you want to get TRULY obsessive you can transcribe the circuit from the comprehensive diagram onto a postcard and work from that.

Oh and Pick up one of those Arkham's Razors...they are great for doing electrical work

unrealworld82 · 03-27-2011, 08:46 PM

OK, so no juice at the connector to the lamps... except when I have someone momentarily pull back on the high beam switch. So, I'm looking at the signal flow and I get it... but what I need to ask is a really rudimentary question. Um, where is the wiring harness for the lamps going? It sort of just disappears into the body behind the headlight motor... and I don't see it again till the fuse box. I have good fuses. Still scratching my head. I guess I need to replace wire from box to lamp. Im wondering if anyone knows of a pic/diagram of how these wires are physically ran so that I know where I am going? I can of course painstakingly trace it, but maybe someone has a pic?