Rear parking light not working but brake light does?!

[machster911]

hello forum friends,

I have a 87 911 coupe, for some reason if anyone can help, while my night parking lights are on the passenger rear tailamps are out. But when I signal right or step on the brakes the lights work? Anyone know what can be causing this problem?? THNKS

[ossiblue]

Parking lights and brake lights are on different circuits and are different bulbs. You could have a bad fuse for the parking lamp on the passenger side. Sorry, I don't know which one it is on an 87, but someone else certainly will.

[machster911]

I tired replacing all the bulbs. Didn't work. So a circuit or a fuse problem possibly? Anyone can say which?

[Joe Bob]

The light that comes on when parked, ignition off and stalk turned down? I would think it's the stalk, how are your blinkers on that side?

[machster911]

Blinkers and brake lights work on passenger side in back, only the parking lights out.

[stevej37]

It's not because of the Euro Parking Light function? Lights come on when key out and turn signal activated?
I only know that it had me stumped for a while on mine...until someone told me about it.

[ossiblue]

Originally Posted by machster911

Blinkers and brake lights work on passenger side in back, only the parking lights out.

You really have to clarify this a bit because there are two parking light functions. The first is when the light switch on the dash is pulled out to the first position. When this is done, all parking lights should come on. The second function, as brought up by several posters, is when the key is out of the ignition and the turn signal stalk is moved up or down, as if making a turn. When that is done, only the parking lights on the appropriate side (right if stalk is up, left if stalk is down) will light--both front and rear.

So, if the rear passenger parking light works when the dash switch is moved out one stop, the circuit is good. If it doesn't light when the stalk is moved up, ignition off, then the switch in the stalk is likely the problem.

[machster911]

Originally Posted by ossiblue

You really have to clarify this a bit because there are two parking light functions. The first is when the light switch on the dash is pulled out to the first position. When this is done, all parking lights should come on. The second function, as brought up by several posters, is when the key is out of the ignition and the turn signal stalk is moved up or down, as if making a turn. When that is done, only the parking lights on the appropriate side (right if stalk is up, left if stalk is down) will light--both front and rear.

So, if the rear passenger parking light works when the dash switch is moved out one stop, the circuit is good. If it doesn't light when the stalk is moved up, ignition off, then the switch in the stalk is likely the problem.

I'm gonna have to try this at home and check it out to see if this works. Thanks for the reply

[stevej37]

Here is a good thread to read that describes the parking light function...http://forums.pelicanparts.com/porsche-911-technical-forum/693199-please-tell-me-not-normal.html

[stevej37]

any results?

[machster911]

I pulled The light switch to first position and none of the passenger parking lights came on. But turn signal would still work

[machster911]

Looks like a blown fuse. Second box 6th one, from forum searches it looks like this is for parking lights right side. Can anyone confirm?

[machster911]

So I replaced the fuse today which fixed the light problem but it blew out within a few hours. abyone know why?

[ossiblue]

Originally Posted by machster911

So I replaced the fuse today which fixed the light problem but it blew out within a few hours. abyone know why?

Time for some sleuthing. First, was the car in motion during the time the lights were on and the fuse eventually blew? I ask because if the car was stationary, that would eliminate the possibility that vibrations cause a wire to short to ground.

Appears to be a high resistance in that circuit. You might start by removing both front and rear light fixtures, remove and clean the connectors to the parking lights--both male and female, reconnect the wires adding a little dielectric grease, and make certain the fixture is securely grounded to the chassis by cleaning that ground connection as well. Before reinstalling each fixture, check to see that all the wires are properly routed and none touch each other. While you're in there, inspect the wires to the parking lights carefully, looking for breaks in the insulation or any bare spots.

Let us know the results.

[machster911]

Originally Posted by ossiblue

Time for some sleuthing. First, was the car in motion during the time the lights were on and the fuse eventually blew? I ask because if the car was stationary, that would eliminate the possibility that vibrations cause a wire to short to ground.

Appears to be a high resistance in that circuit. You might start by removing both front and rear light fixtures, remove and clean the connectors to the parking lights--both male and female, reconnect the wires adding a little dielectric grease, and make certain the fixture is securely grounded to the chassis by cleaning that ground connection as well. Before reinstalling each fixture, check to see that all the wires are properly routed and none touch each other. While you're in there, inspect the wires to the parking lights carefully, looking for breaks in the insulation or any bare spots.

Let us know the results.

I checked all the ground connection everything seems clean , also checked all wires nothing seems to be damaged or loose but did come across these 3 wires that aren't connected anywhere. Sorry still new to this Porsche thing hopefully these pics would help

[James Brown]

keep going your on the right track, try to look at the bulbs and sockets at the side that is out. most likely corrosion or damage to the wires is causing this high resistance. lets work on one problem at a time! plenty of time

[ossiblue]

Originally Posted by James Brown

keep going your on the right track, try to look at the bulbs and sockets at the side that is out. most likely corrosion or damage to the wires is causing this high resistance. lets work on one problem at a time! plenty of time

+1.

"Checking", as mentioned in your post, doesn't mean much, IMO, without some detail as to what that entailed. You need to do some serious inspections which includes removing the fixtures on the side that doesn't work. I offered up some basic steps as to how far, at least, you need to go upon first investigation. Your reply doesn't seem to indicate you put too much effort into the task. If I'm incorrect, I apologize, but we only know what you do through your posts.

Here's what we know:

1) Passenger side parking lights failed to light due to a blown fuse.

2) Fuse was replaced, lights worked.

3) After about an hour, fuse blew.

Here's what we don't know:

1) Was the car moving when the fuse blew?

2) What is the condition of the sockets for the parking lights (inside, with bulb removed, as well as outside at connectors)?

3) What is the condition of the light fixture, including all connections to chassis ground?

4) Does the fuse blow when either the front or rear light is disconnected?

5) Are all the wires that are connected to the light fixtures (besides the parking lights) separated from each other?

6) What is the condition of the wiring loom, from the light fixtures to the chassis?

7) Have you traced the wires from the blown fuse as far as possible, looking for bare spots?

If you can answer the seven questions, above, that would help greatly--especially #4 as that could isolate the source of the problem.