Interior lights and switches stopped working
03-24-2017, 10:27 PM
#16
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Circling back to this post...
I did confirm that fuse #12 in the drivers side (left) fuse panel protects the interior light circuit and should be 20A. Last weekend I pulled the overhead console to check the condition of the light switch. It was perfect. No melted plastic and good, clean contact points. Interestingly, with the overhead panel out I tried installing another fuse in the #12 slot and it again blew immediately. So evidently the cause of the short is not within the overhead panel itself. I'm still trying to track down a wiring diagram so that I can see what components are on this circuit. That way I can start checking one by one.
I did confirm that fuse #12 in the drivers side (left) fuse panel protects the interior light circuit and should be 20A. Last weekend I pulled the overhead console to check the condition of the light switch. It was perfect. No melted plastic and good, clean contact points. Interestingly, with the overhead panel out I tried installing another fuse in the #12 slot and it again blew immediately. So evidently the cause of the short is not within the overhead panel itself. I'm still trying to track down a wiring diagram so that I can see what components are on this circuit. That way I can start checking one by one.
There are no other components on this circuit. The wire from fuse #12 in left dash fuse panel only goes to the CONTROL UNIT. In diagrams the terminal it goes to on the CONTROL UNIT is called "K1" - "TERM 30 Inside Light" - in Porsche speak - TERM 30 just indicates it's a power feed, there are several connections to the control unit with the "TERM 30" annotation next to them. That wire is RED/WHT.
"K2" is shown as exiting the control unit going to the "Interior Light System" - That wire is RED.
It's somewhat complicated from there out -- I have two PDF pages showing the Fuse-12 connection to the control unit. I suspect if you unplug the control unit the fuse will stop blowing. Problem is - is the short in the control unit (think major $$ and I believe it has to be programmed to the vehicle) or somewhere downstream.
The circuit out of the control unit goes to the overhead console, the makeup lights in the sun-visors (I'd be very suspicious of the wire leading through the pivot for these), and perhaps to the left and right overhead lights in the rear seat. And maybe to the overhead light in the rear trunk compartment.
As a start - you might try disconnecting the overhead console from the circuit and see if the fuse still blows. If it doesn't - the problem is in the console. If it does blow - the console can be removed from the list of suspects.
If you want to PM me an email address I'll send a few PDFs. Shame but we can't upload them here.
Last edited by deilenberger; 03-25-2017 at 01:01 AM.
03-25-2017, 07:23 PM
#18
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Success! I removed the driver's side sun visor and saw that the jacket and insulation had worn right through on the wires for the visor mirror light. The wires were clearly shorting on the metal of the headliner. Repaired the wires, installed a new fuse and all is perfect again. Big thanks to Don for the insight and the wiring diagrams!
10-15-2022, 05:15 PM
#20
My one suggestion - check the operation of the sliding switch right above the mirror (dead center near the windshield) on the top console. That's the switch for the interior lights. It comes apart. If it moves very easily - the sliding metal contact in it has come apart. It would then be drifting around inside the console and could be causing your problem. Porsche has a kit to fix that switch.
955613300016n3
Could anyone shed some light on what gets swapped out/in with this kit? Thanks!