dmaddox's 1993 C2 Workshop
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dmaddox's 1993 C2 Workshop
Starting a thread to keep all projects for my recently acquired 964 under one roof. All work is on a 1993 C2, 5 Speed:
Table of Contents
Table of Contents
- Adjusting the Ride Height on PSS10's
- BBi Uprights Parts and Installation
- Front "Smile" bumper trim replacement
- Ignition upgrade 964 --> 993
- Momo Steering Wheel & Turn Signal assembly
- Rennline Adjustable Motor Mounts and Tubular Engine Carrier
- Rennline Strut Tower Brace Install
- Rothsport Short Shifter Install, with FD Forward and Golden Rods
- Right rear turn signal, not blinking, dash indicates a rapid blink
Last edited by dmaddox; Jan 16, 2023 at 01:48 PM.
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Thank you all! I was able to chase down the problem using the provided diagrams and other threads. The issue was the trunk light plug was plugged into the spare market light plug just by the right side hood support. I swapped the plugs and replaced the #33 7.5A fuse - and we are good.
This is presenting a new problem - which probably created the first! The trunk light stays on. I researched as well - indicating if the doors are open it will stay on, etc.. However I used my cell phone and recorded closing everything, waiting 20 seconds and then opening it again. After reviewing the video on my phone, the light inside the trunk never went off.
Work around, just keep the trunk light unplugged - however I would like to have it come on as intended. You know....late night grocery runs and all.....
I searched everywhere around the lip of the trunk for a plunger that depressed when closed...can't see anything obvious.
Any ideas while I go back to the drawing board/diagrams?
edit: I know for 993 but I have that device on my hood latch as well. I'll give it a go... https://rennlist.com/how-tos/a/porsc...e-trunk-383238
Cheers and thanks again!!
This is presenting a new problem - which probably created the first! The trunk light stays on. I researched as well - indicating if the doors are open it will stay on, etc.. However I used my cell phone and recorded closing everything, waiting 20 seconds and then opening it again. After reviewing the video on my phone, the light inside the trunk never went off.
Work around, just keep the trunk light unplugged - however I would like to have it come on as intended. You know....late night grocery runs and all.....
I searched everywhere around the lip of the trunk for a plunger that depressed when closed...can't see anything obvious.
Any ideas while I go back to the drawing board/diagrams?
edit: I know for 993 but I have that device on my hood latch as well. I'll give it a go... https://rennlist.com/how-tos/a/porsc...e-trunk-383238
Cheers and thanks again!!
Last edited by dmaddox; Sep 21, 2021 at 05:51 PM.
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The plunger contact is in the frunk lid in far passenger side corner right by the strut that holds it open. The contact plunger hits a metal bracket in the trunk. Make sure it is not bent down. If it is the contact will not open and the light stays on. It's easy to just bend the metal bracket back into position.
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I think at some point the 964 was upgraded to the 993 trunk light relay unit at the latch, as pictured in the above link. I don’t have a plunger anywhere around the perimeter of the frunk.
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Was working on the small metal u-shaped actuator moving it up and down no manner of fiddling with that actuator shuts the light off. At a loss. Will dig into the wiring diagrams.
Last edited by dmaddox; Sep 21, 2021 at 11:07 PM.
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Now this is strange......I was reading another post about the door contact switch also causing this behavior. And...I was about to order a new door contact switch because when I opened my door (with both interior lights in position B...or "on" when door is open) and I pushed in the door contact the interior light stayed on.
However, get this....I realized the hood was open (from me testing the hood latch). So, I left both interior lights in position B and closed the doors, then I went out and closed the hood....boom, both interior lights went off! This tells me that both door and hood latch switches all work!!
Excited, I popped the hood again, and plugged in the luggage light that I ended up disconnecting so it would go off....and closed the hood again thinking I was good to go. However....the light in the luggage dept AND the interior stayed on when I closed the hood. Huh? How is this possible.
Luggage/trunk light unplugged - interior lights go off when trunk/doors are closed.
Luggage/trunk light plugged in - all lights stay on when trunk/doors are closed.
What the devil? Why would plugging in the luggage/trunk light cause all of the lights to remain on? Electrical gremlins are the work of satan.
However, get this....I realized the hood was open (from me testing the hood latch). So, I left both interior lights in position B and closed the doors, then I went out and closed the hood....boom, both interior lights went off! This tells me that both door and hood latch switches all work!!
Excited, I popped the hood again, and plugged in the luggage light that I ended up disconnecting so it would go off....and closed the hood again thinking I was good to go. However....the light in the luggage dept AND the interior stayed on when I closed the hood. Huh? How is this possible.
Luggage/trunk light unplugged - interior lights go off when trunk/doors are closed.
Luggage/trunk light plugged in - all lights stay on when trunk/doors are closed.
What the devil? Why would plugging in the luggage/trunk light cause all of the lights to remain on? Electrical gremlins are the work of satan.
Last edited by dmaddox; Sep 22, 2021 at 11:47 AM.
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Actually it may make sense because unplugging the trunk light breaks the connection just as the switch does when the trunk is closed. Both create an open circuit indicating that the trunk appears closed.
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Not following you, sorry. I honestly don't see how having the light plugged in would have them all stay on, unless there is a circuit (positive) wire feeding that light constant power. I say this because when it is unplugged, and I close the hood, the interior lights go out. How would the interior lights know to go out if either of the doors or front hood latch were faulty?
So, at this point....as a work around (while I prefer to have it operate normally) I am leaving the light unplugged...
So, at this point....as a work around (while I prefer to have it operate normally) I am leaving the light unplugged...
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I have '91 964 Targa and the interior light stays on if the trunk light is on even with the trunk closed. In other words, unless you have an open circuit in the trunk (either through a functioning switch or the bulb unplugged) the interior light remains on. Btw, if you have a factory alarm, you will see the blink sequence of the door **** indicating a fault if your trunk light stays on.
It is possible that Porsche did this on purpose in an era before cell phones to prevent a constant on trunk light from draining the battery. The original 964 had a bracket that could bend out of shape preventing the trunk switch to engage.
It is possible that Porsche did this on purpose in an era before cell phones to prevent a constant on trunk light from draining the battery. The original 964 had a bracket that could bend out of shape preventing the trunk switch to engage.
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Here is my post in another battery drain thread, that started with the same observations re: interior and frunk/engine lights. It may not be the identical root cause, but might highlight that there is a link between a short in a circuit and the alarm system. Can you set the alarm system when you lock the door with the key?
https://rennlist.com/forums/964-foru...l#post17183999
https://rennlist.com/forums/964-foru...l#post17183999
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Thank you all for the advice as I work through this weird lighting issue. I have locked the car with the key and observed the alarm light - (with the luggage light still unplugged) and it blinks quickly for about 5 seconds and then slows to a pulse. So, according to documentation the alarm is ok and not part of the problem.
At this point I'm tempted to just install an antique lamp pull chain and when putting groceries in the car, just pull on the ol lamp chain..."click-click" and on the light comes, then "click-click" the light go off, shut the hood and off I go. As annoying as this light situation is....at least that would be a conversation starter.
At this point I'm tempted to just install an antique lamp pull chain and when putting groceries in the car, just pull on the ol lamp chain..."click-click" and on the light comes, then "click-click" the light go off, shut the hood and off I go. As annoying as this light situation is....at least that would be a conversation starter.
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I’m not entirely following the description, but the ‘93 models use the same frunk light trigger as 993. Sticky door plunger switches are not unusual- my new one wouldn’t make contact in cold weather only because the rubber cover wouldn’t flex enough when the door opened.
In any case, you can replace the frunk/engine/interior festoon bulbs with led versions. Much brighter and very little current draw in case one gets stuck on.
In any case, you can replace the frunk/engine/interior festoon bulbs with led versions. Much brighter and very little current draw in case one gets stuck on.
Last edited by -nick; Sep 23, 2021 at 11:01 AM.