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Replacing some wires to the interior lights.
Can anyone tell me what gauge wires are used?
Specifically the rear dome light.
Does anyone sell wire that has the Porsche factory colors?
For example brown with white stripe.
thanks
Porsche 928 Wiring Diagrams
That being said, the 1989 wiring diagrams are some of the most difficult to read so look to 1990 for clarity. Most systems are unchanged. The metric wire diameter for all the accessory lamps is 0.75mm.
19 gauge (.75mm) wire is probably hard to find in the US. Here's a source for similar 18 gauge that should work fine. They have lots of other colors to choose from as well. https://lswiring.com/products/18-awg...D&gad_source=1
I did end up going with 19 gauge due to 18 being very hard to find,
I was trying to look at the 89 electrical diagram and really could not read it-
thank you
does anyone know where this connection of three wires attaches?
it is behind the rear hatch light and goes towards the center latch-
On the passenger side I have the white, green, and brown running up the hatch to the rear center light.
On the drivers side it is blue, brown, and green with a yellow stripe going towards center of the rear of car.
I assume it is a piggy back similar to the rear dome light, but I was unable to find it on the wiring diagram and in any pictures on line.
I followed the wire from the light under the rear of the hatch towards the drivers side.
The brown, blue, and green with yellow stripe go into a 3 wire white connector.
the blue turns into a white
the brown in the middle stays brown
the green and yellow stripe turns to green.
Not sure what the purpose was for this color change on such a short wire connection.
i guess looking behind a 928 fuse panel tells you everything you need to know about German Porsche 928 wiring.
The wire with the Blue, Brown & Yellow/Green is not a Porsche wire - someone added that (standard European 220V power cable colors). So you are not the first in there... stock color in the roof would be White, Brown & Green as on the other side of the connector (same function as Brown/White, Brown & Red respectively for the door lights.
Interestingly the Euro power cable uses Yellow/Green as Ground/Earth, Brown as Live, Blue as Neutral, so not as you might think based on Bosch color schemes.
The white connector on the drivers side of the hatch light does look factory,
It seems to change the standard white/green/brown coming from the drivers side to blue/yellow-green stripe/brown into the light.
Possibly this is to distinguish a power, ground, and switched ground coming from a different source.
The hatch does shut all lights immediately when closed bypassing the interior light delay relay.
(guessing)
Maybe someone with an 89, can look at the wiring to the rear hatch light.
On a positive note, I hooked up the 2 door lights, front, rear dome, and hatch with alligator clips to test.
All seems to be working correctly, including the 25 second interior light delay relay.
I am using 2 VW lights for the front and rear dome, stock door lights, all with LED.
For the rear hatch many have said the VW light won't fit correctly.
I had an extra door light, which I think will work good in that location with an LED-eliminating the dreaded chassis ground.
Has anyone ever used a door lamp in the rear hatch location?
Last edited by PC-85-928S; 04-12-2024 at 03:36 PM.
My car is an '88, ROW version. Hopefully this photo will help.
Two wires on the left are white and brown/gray (or br/wh - hard to see). To the right are green and red. The one at the back is the ground - brown.
The wiring diagram is almost impossible to read, but it seems the only difference between ROW and USA models is the addition of a 'stoplight' for the USA.
Someone has definitely changed the wiring on your light. You will need to check continuity between the CE and the plug, then from the plug to the light.
The second dome light, nearest the tail gate latch just has three wires. Brown, green and white.
The white connector on the drivers side of the hatch light does look factory,
It seems to change the standard white/green/brown coming from the drivers side to blue/yellow-green stripe/brown into the light.
Possibly this is to distinguish a power, ground, and switched ground coming from a different source.
The hatch does shut all lights immediately when closed bypassing the interior light delay relay.
(guessing)
...
It is just a random replacement wire connected in place of the stock wiring (presumably there was a reason...). The rear hatch switch directly switches the brown/white (or white) wires to ground to turn on, while the door pin switches trigger the delay relay to ground the brown/white wire with delayed off - that is the only difference - all the wiring to the lights is wired in common (including the hatch).
My car is an '88, ROW version. Hopefully this photo will help.
Two wires on the left are white and brown/gray (or br/wh - hard to see). To the right are green and red. The one at the back is the ground - brown.
The wiring diagram is almost impossible to read, but it seems the only difference between ROW and USA models is the addition of a 'stoplight' for the USA.
Someone has definitely changed the wiring on your light. You will need to check continuity between the CE and the plug, then from the plug to the light.
The second dome light, nearest the tail gate latch just has three wires. Brown, green and white.
This fixture is wired incorrectly - so a poor example - the red and green wires should be at the end with a single connection - swap with the Brown/White & White wires.
This fixture is wired incorrectly - so a poor example - the red and green wires should be at the end with a single connection - swap with the Brown/White & White wires.
Alan
Thank you for your sharp eyes and knowledge!
I pulled the light to take that photo this morning hoping it would help PC-85-928S.........and knowing I had a lighting issue that I would need to resolve one day when I got the car back on the road.
You may well have solved the 'non-working interior light problem' for me!
I think that is your rear dome.
We are wondering if the brown/green-yellow/blue coming in from the drivers side to the hatch light is stock.
I feel it is due to the white connector, and the wire shielding.
Alan thinks it is aftermarket.
Thanks
04-08-2024, 08:36 PM
89 INTERIOR LIGHT QUESTION
