Porsche 930 Interior Lights

[carrpet]

Hi All,

Could do with some of your help and experience here.

Its a 930 convertible a 1989 930.66

I have a fault with my interior light and could do with some help on the diagnostics please.

Firstly the interior light can be turned on permanently by rotating the light so that the side nearest the windscreen is uppermost

Secondly both door switches can independently be heard operating a "relay" or equivalent under the dash. Is this connected with window operation, the alarm or a buzzer ?

The trunk light comes on as soon as the trunk is raised (no keys required in the ignition)

The engine compartment light comes on with the side lights when the engine lid is raised.

Not sure which position is the "off" position for the interior light. I assume its the middle position ?

When the interior light is in the third position I can't get the light to come on at all.

I had assumed the door contact switches were faulty, and I have bought replacements, but the existing switches are definitely operating a relay of some sort which I can hear.

Can you help me shed some light on this problem and on the interior of my car when I open the doors ?

Thanks

[darrin]

Power windows use a relay to remain operational after removing the key until a door is opened -- triggered by the door contact switch (at least on newer 911/930s -- they do on my '86 targa) -- if your 930 is relatively late production, you should start by confirming that this works -- that you can operate your power windows after shutdown with doors closed and that opening either door causes the power windows to stop working -- this will confirm that your door switches do, in fact, work.

[carrpet]

Originally Posted by darrin

Power windows use a relay to remain operational after removing the key until a door is opened -- triggered by the door contact switch (at least on newer 911/930s -- they do on my '86 targa) -- if your 930 is relatively late production, you should start by confirming that this works -- that you can operate your power windows after shutdown with doors closed and that opening either door causes the power windows to stop working -- this will confirm that your door switches do, in fact, work.

Great input, thanks will test tomorrow and report back ! It's one of the last 930's made (1989) so my guess is you are right.

[carrpet]

Originally Posted by darrin

Power windows use a relay to remain operational after removing the key until a door is opened -- triggered by the door contact switch (at least on newer 911/930s -- they do on my '86 targa) -- if your 930 is relatively late production, you should start by confirming that this works -- that you can operate your power windows after shutdown with doors closed and that opening either door causes the power windows to stop working -- this will confirm that your door switches do, in fact, work.

Have tested this out.

The windows continue to operate if either one of the doors are open. If both doors are closed the windows stop operating !! This sounds incorrect and suggests the wiring (the relay wiring ? is incorrect, but the switches are working !

Peter

[msterling]

Windows should work after shutdown with doors closed. Open one door and they still should work. Close the door and windows should not work. This to de-energize your windows after you leave the car as the relay draws power and will drain the battery. Both doors do the same thing.

Rock light forward=always on. Middle position=always off. Rock back=light on with door open.

[darrin]

Originally Posted by msterling

Windows should work after shutdown with doors closed. Open one door and they still should work.

Not sure this is the case -- it's my understanding that opening either door triggers the circuit and shuts off power to the window. Otherwise, if driving solo (opening only one door), the circuit wouldn't deactivate.

[carrpet]

Either way the door switches do appear to be working but my interior lights do not operate so I still need help !

[msterling]

Maybe the switch inside of the interior light is malfunctioning.

[Chuck.H]

My light assembly failed early on in ownership and I replaced it.

IIRC, part of the plastic broke and would no longer let the brass make contact in one of the positions. If you take the light out and apart, you can see how it operates and determine if this is your problem.

Chuck.H
'89 TurboLookTarga, 427k miles

[darrin]

per the above 2 posts, seems like the best next step would be to use a voltmeter or circuit tester to examine whether the light assembly is getting power from the circuit that's activated by the door switches.

[carrpet]

Originally Posted by msterling

Maybe the switch inside of the interior light is malfunctioning.

Yes you are right I need to test the light unit / switch assembly

[carrpet]

Originally Posted by darrin

per the above 2 posts, seems like the best next step would be to use a voltmeter or circuit tester to examine whether the light assembly is getting power from the circuit that's activated by the door switches.

Thanks will take a look next

[carrpet]

Originally Posted by darrin

per the above 2 posts, seems like the best next step would be to use a voltmeter or circuit tester to examine whether the light assembly is getting power from the circuit that's activated by the door switches.

Will do !
The door switches connect the light circuit to earth, and as the light will operate on permanently on position 1, I presume I will find 12v at the light ok, but possibly not switched earth ? Or the unit is faulty !

[carrpet]

If anyone can point me at the relevant wiring diagram for the interior lights, door contact switches, and window relay, it would be much appreciated ?

[msterling]

Complete parts diagrams HERE

[carrpet]

Sorry for the delay, I have been away a few days:

To investigate further, I removed both light fittings ; the one above the centre of the windscreen and the one next to the glove compartment. The light fitting above the centre of the windscreen was faulty and was not making contact with the switched earth in the door pillar. The plastic was distorted and cracked so I had to replace the unit. All is working just fine on the centre light now.

However, there are 2 issues with the light fitting next to the glove compartment.

Problem 1 is faulty earth switch in the glove compartment itself. There appears to be no slack wire behind it so I can get the switch out more than about 2cm. Has anybody else experienced this problem, and are there any ideas out there as to how to free it up without a lot of work removing items from under the dashboard.

Problem 2 is that I would rather have this light coming on when the passenger door is opened, than when the glove compartment is opened. Is there a convenient way of achieving this ?

[DaveMcKenz]

Originally Posted by carrpet

Sorry for the delay, I have been away a few days:

To investigate further, I removed both light fittings ; the one above the centre of the windscreen and the one next to the glove compartment. The light fitting above the centre of the windscreen was faulty and was not making contact with the switched earth in the door pillar. The plastic was distorted and cracked so I had to replace the unit. All is working just fine on the centre light now.

However, there are 2 issues with the light fitting next to the glove compartment.

Problem 1 is faulty earth switch in the glove compartment itself. There appears to be no slack wire behind it so I can get the switch out more than about 2cm. Has anybody else experienced this problem, and are there any ideas out there as to how to free it up without a lot of work removing items from under the dashboard.

Problem 2 is that I would rather have this light coming on when the passenger door is opened, than when the glove compartment is opened. Is there a convenient way of achieving this ?

Good morning.
I think 2 cm. is enough to remove the glove compartment contact switch, and clean it. Put a hemostat or tie a wire to the male connector on the wire so it does not drop out of sight.
To make this light come on with the PS door you need to find the brown wire above the PS kick panel and tap into this. Then run a wire to the place wire the glove compartment light is and connect to the switched ground connection of that light. I will then come on when either door is opened. You would need to separate the switched grounds from the two doors to change that. Not sure where to do that or if it's worth the trouble.
Good luck,
Dave

[msterling]

The interior lights of the Carrera Cab are pretty dismal including the dash illumination. Search for LED options that are much brighter. Glad you fixed the dome light. It should come on when either door is opened. Rewiring the glove box light would disable its original purpose but should be doable as described above. When working, the glove box light should come on when rocked forward or if the glove box is opened. It is disabled when in the middle position and is normally left rocked toward the rear of the car. It is kinda nice to have a light mounted low that can be turned on by a passenger without making it difficult for the driver to see the road.

[carrpet]

Originally Posted by DaveMcKenz

Good morning.
I think 2 cm. is enough to remove the glove compartment contact switch, and clean it. Put a hemostat or tie a wire to the male connector on the wire so it does not drop out of sight.
To make this light come on with the PS door you need to find the brown wire above the PS kick panel and tap into this. Then run a wire to the place wire the glove compartment light is and connect to the switched ground connection of that light. I will then come on when either door is opened. You would need to separate the switched grounds from the two doors to change that. Not sure where to do that or if it's worth the trouble.
Good luck,
Dave

Thanks Dave,
will take a look in the next 2 days

[carrpet]

Originally Posted by carrpet

Thanks Dave,
will take a look in the next 2 days

Thanks Dave worked perfectly