SWB - Which relay for Parking Lights?

[TargaFlorio]

Hi guys,

I have a broken parking light, front right.
The Fuse is good and I put in a new bulb so I'm thinking it might be the relay.

Do the parking lights go through the blinker relay or the headlight relay?

I looked at the wiring diagram but I didn't go to M.I.T.

This is a Euro car so it has the parking light function. When I put the blinker stalk in the up (right blinker) position the rear parking light comes on (the front one doesn't work).

When I pull the headlight switch into the first position, all the parking lights work except for the front right.

The blinkers work fine on both sides.

Headlights Low/High beam work fine.

Any help would be greatly appreciated.

Cheers,
http://nicolashunziker.com

[911s55]

Are those dual filament bulbs?
Just realized, SWB Euro is twin bulb configuration, correct?

[HarryD]

As near as I can tell from the '65 diagram, there is no relay in the parking light circuit. Most likely you have a loose connection someplace.

To figure out the circuit (assuming you have a diagram), often the best way to do is to make a copy and use a highlighter to trace the circuit. Start at the item that appears to not work and trace it all the way to ground and to the battery. The diagram will show you what components are in the circuit. To save on wiring, often Porsche will use a common point to connect several things. Each device has a pictorial representation of how the guts work. If you have a question about a device ask.

[TargaFlorio]

Yes, single filament bulbs.

Cheers,
http://nicolashunziker.com

[TargaFlorio]

Harry,

when you say

"trace it all the way to ground and to the battery"

should I cut open the insulation that holds several wires together? The wire from the parking light (that is broken) leads into a thicker cord that is insulated and also carries the wires from the headlights.

Cheers,
http://nicolashunziker.com

[911s55]

Aren't there two bulb locations in each assembly?

Relays are: as per PET 68'
directional indicator flasher-1
headlight flasher-1
horn, heater blower, ignition coil-1

[TargaFlorio]

Yes, 1 bulb (located towards the front) is the parking light.
The 2nd bulb (located more towards the side) is the blinker.

Cheers,
http://nicolashunziker.com

[HarryD]

Originally Posted by TargaFlorio

Harry,

when you say

"trace it all the way to ground and to the battery"

should I cut open the insulation that holds several wires together? The wire from the parking light (that is broken) leads into a thicker cord that is insulated and also carries the wires from the headlights.

Cheers,
http://nicolashunziker.com

NO, do not cut the harness.

Find a copy of the wiring diagram from a shop manual. Trace it on paper to see where the circuit goes. The diagram will also give you the colors ofhte wires so you can identify them inthe harness.

Did the light work at one time and then stop?

Do you have a voltmeter or a 12V test light? Do you have power on the terminal in the lamp housing when you turn on the lights?

[TargaFlorio]

I do have the shop manual/diagram, it looks like spaghetti to me but I'll try to trace the parking light wire.

Yes, the light was working. The bulb burned out and I replaced it with a new one and it's still not working.

Don't have an volt meter. I'm assuming that I have power in the lamp housing because the blinker works.

Cheers,
http://nicolashunziker.com

[911s55]

Sounds like its bad at the switch or socket, just a hunch.
Good luck!

[HarryD]

Originally Posted by TargaFlorio

I do have the shop manual/diagram, it looks like spaghetti to me but I'll try to trace the parking light wire.

Yes, the light was working. The bulb burned out and I replaced it with a new one and it's still not working.

Don't have an volt meter. I'm assuming that I have power in the lamp housing because the blinker works.

Cheers,
http://nicolashunziker.com

Before you mess with the drawing, look below.

The two bulbs are on separate circuits. They should not affect each other.

Some times a new bulb is bad. Look at the inside of bulb and verify that the filament is intact.

It is possible that the little tab inside the lamp housing is not touching the base of the bulb (I had that happen to my housing). You may need to bend the tab up a touch to make it contact the bulb. you can test for power at this point, by using a 12v test lamp. You ground one side of the lamp and carefully try to touch the tab in the housing while it is energized (if you short to ground, you will blow out the fuse). If the lamp lights, the problem is poor contact between the lamp and the housing. You may need to remove the housing to get access to the contact (and you be at risk of breaking something as well). Only you can decide how far you wish to go with this.

If you want to mess with the drawing, enlarge it 2-3x first. Get a thin highlighter and follow the appropriate lines. The nice part about Porsche's early diagrams is that they show the routing of the wires as they run through the car. If you look, you will note that the components are located on the drawing as they are in relationship to each other in the car (i.e. the headlamps are on the upper top corners, the gauges are in the middle, the taillights are in the lower corners etc). As a result the wires may look like they run in randomly but this is how they are run through the car.

[HarryD]

Originally Posted by 911s55

Sounds like its bad at the switch or socket, just a hunch.
Good luck!

If it is only one light, then I would say it is the at the lamp housing, otherwise all of the lights would not work.

[TargaFlorio]

Harry,

I was looking for the '68 diagram but couldn't find it. The only one I could find is '69 and later. They may be the same but the '68 has only one battery so it might be different?

Either way, I was just in the garage and switched the bulbs; front right still doesn't work.
I bent up the little tab as well, I actually did that when I installed the bulb the first time around (it looked a little loose and low to me).

I'll try to see if I'm actually getting power to the housing with a test light.

Cheers,
http://nicolashunziker.com

[HarryD]

Originally Posted by TargaFlorio

Harry,

I was looking for the '68 diagram but couldn't find it. The only one I could find is '69 and later. They may be the same but the '68 has only one battery so it might be different?

Either way, I was just in the garage and switched the bulbs; front right still doesn't work.
I bent up the little tab as well, I actually did that when I installed the bulb the first time around (it looked a little loose and low to me).

I'll try to see if I'm actually getting power to the housing with a test light.

Cheers,
http://nicolashunziker.com

The '65 diagram here: http://www.pelicanparts.com/911/911_Parts/911_electrical_diagrams.htm may be more valid. Take a look. The wire you are interested in is the red and white striped one.

It was a while ago when I had my problems and as best I recollect, it took a while to get the parts properly in contact with each other. Part of the problem I had was getting the outter part of the lamp base to contact the housing.

With the power on, try gently wiggling (or pressing) the bulb in the socket to see if it is making contact. It is also possible that the outter part of the bulb is not contacting the housing to complete the circuit to ground. When you wiggle it you may help it make contact.

BTW: nice art work.

[TargaFlorio]

I got it to work. The culprit was a that little tab that holds the bulb assembly to the turn-signal unit. So basically it was a bad ground to the parking light bulb.

Thanks so much for all your help!

Cheers,
http://nicolashunziker.com

[HarryD]

Congrats!

One last thought, if you have not already, pull the bulbs out and put on a thick coat of Dielectric Grease on the base and replace. This will help reduce corrosion and help the bases last longer.