Licence plate lights - always on!! (fixed!!)
12-11-2004, 11:28 PM
#1
Track Day
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Location: NY
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Licence plate lights - always on!! (fixed!!)
Usually most people have the opposite problem - no licence plate lights! In my case the plate lights are always on even when the the main light switch is turned off...They stay on even when the ignition is off and the key out!!!
I located fuse #3 which controls the licence plate lights plus the engine compartment light. I don't have one there and I don't need it....When I pull the fuse of course the licence plate lights go out....I noticed there are two (2) wires connected to the lights; a green and a brown...I assume the brown wire is the ground and the green the switched power source...
I've replaced the main lights switch (on the pod) with a good one trying to eliminate a possible bad switch but it didn't fix my problem....Does anyone have any suggestions what to look for??
Thanks
Bill
'83 928S 5-spd cream
I located fuse #3 which controls the licence plate lights plus the engine compartment light. I don't have one there and I don't need it....When I pull the fuse of course the licence plate lights go out....I noticed there are two (2) wires connected to the lights; a green and a brown...I assume the brown wire is the ground and the green the switched power source...
I've replaced the main lights switch (on the pod) with a good one trying to eliminate a possible bad switch but it didn't fix my problem....Does anyone have any suggestions what to look for??
Thanks
Bill
'83 928S 5-spd cream
Last edited by galatsi; 12-13-2004 at 05:05 PM.
12-12-2004, 03:54 PM
#3
Bill,
Checked the WSM and it appears the license plate light gets switched power from the light switch. The same circuit provides power to the fog light switch (light?). Could you be getting stray power from the fog light switch?
Dennis
Checked the WSM and it appears the license plate light gets switched power from the light switch. The same circuit provides power to the fog light switch (light?). Could you be getting stray power from the fog light switch?
Dennis
12-13-2004, 05:05 PM
#4
Track Day
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Solved the "always-on" licence plate lights problem!
Disconnected the battery and cleaned ALL the fuse terminals and replaced ALL the fuses with new ones on the fuse panel...Somehow the problem is now fixed...Just like that - nothing else was done!
My guess is that something was either corroded or not making good contact down below...
.....on to the next problem
Bill
'83 928S Ivory 5-spd
Disconnected the battery and cleaned ALL the fuse terminals and replaced ALL the fuses with new ones on the fuse panel...Somehow the problem is now fixed...Just like that - nothing else was done!
My guess is that something was either corroded or not making good contact down below...
.....on to the next problem
Bill
'83 928S Ivory 5-spd
12-16-2004, 01:49 AM
#6
Developer
I cannot repeat often enough how many electrical gremlins are caused by patina on the fuse panel.
Those damn ceramic fuses and their little copper caps... when copper oxidizes it makes a pretty green coating called patina - and unfortunately (and ironically for such a good conductor as copper) patina is an excellent insulator.
Some of the circuits in the 928 are positive switched and always grounded. Others have a switched ground and are normally insulated.
This combination makes feedback thru a blocked or shunted circuit entirely probable.
Before you spend hours with a test light in your 928 chasing electrical gremlins, take an ink eraser to your fuse panels contacts to brighten them up and replace all your fuses. Many, many intermittent problems disappear this way.
A permanent solution: the stainless steel/glass cylinder fuses that we sell for the Porsche take those damn ceramic pieces of crap and pull them into the 21st century. Here they are if you are interested:
http://www.928motorsports.com/parts/fuses.html
Keep in mind that even Porsche ditched those fuses when better technology became available later - why shouldn't you?
Those damn ceramic fuses and their little copper caps... when copper oxidizes it makes a pretty green coating called patina - and unfortunately (and ironically for such a good conductor as copper) patina is an excellent insulator.
Some of the circuits in the 928 are positive switched and always grounded. Others have a switched ground and are normally insulated.
This combination makes feedback thru a blocked or shunted circuit entirely probable.
Before you spend hours with a test light in your 928 chasing electrical gremlins, take an ink eraser to your fuse panels contacts to brighten them up and replace all your fuses. Many, many intermittent problems disappear this way.
A permanent solution: the stainless steel/glass cylinder fuses that we sell for the Porsche take those damn ceramic pieces of crap and pull them into the 21st century. Here they are if you are interested:
http://www.928motorsports.com/parts/fuses.html
Keep in mind that even Porsche ditched those fuses when better technology became available later - why shouldn't you?
