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Discussion Starter #1 (Edited)
My rear trunk light wasn't coming on when opened, so I went through these steps to troubleshoot, and I'm stuck now.

Car has 'alarm system' according to the sticker. 'Frunk' lights behave as expected.

Pulled the bulb and hooked it up to 12V. Conclusion: Bulb glows and is good.

Disassembled the rear trim and checked the switch on the striker assembly. Switch works. I hooked up a meter to it after disconnecting the harness and found the switch closed when the trunk was open and an open circuit when the trunk was closed. Conclusion: Switch is good.

Reconnected the switch harness. Locked the car with the trunk opened and closed. The lock button light on the dashboard behaved differently in each case. When the trunk was closed, it pulsed around 20 times and then went to a very occasional short flash. When the trunk was opened and I locked the car, it would flash 15 groups of 2 flashes. However, the horn did NOT honk when the trunk was open. I read that it should elsewhere on the forum. Conclusion: Car can tell if the trunk is open because the electrical connection from the switch is good, but does not sound the horn.

Repeated this test by disconnecting harness and manually shorting the connection on the harness going to the car and got the same results as before. Conclusion: Everything works as it did before, just confirming and sure the switch is fine now.

Changed the electrical shorting on the harness to the car when the car was 'locked'. This caused the lights to pulse continuously, like the alarm was going off. No horn though. Was easily reset from the key.

Locked the car with the 'frunk' open. Lock LED also did 15 blinks of two flashes, like when the rear trunk was open. No horn. Conclusion: Behavior of 'no horn on lock' with either trunk open is consistent.

Still didn't have a trunk light though, so I put a meter on the trunk light harness with the bulb assembly unplugged. Trunk light is showing 5.89V whether the trunk is open or not and this is not enough to make the bulb go on. Conclusion: ?????

So, two questions:

1. I just had a PPI on this car and the dealer didn't mention the alarm horn not working. Frankly, I didn't know that it should, I assumed it just blinked. Could it be dealer disabled in software? Do these fail? I validated that the alarm horn is plugged in and Fuse 3 in Row B is good - I assume if it was dealer disabled for lock chirp, it would still work for alarm. Tomorrow I can pull the horn out and test.

2. What in the heck would cause 5.89V to be delivered to the rear trunk bulb at all times? I'm used to seeing 0V or 12V at a point like this, this feels very wrong. Searches for 6V porsche just loads me up with 356 hits, I can't seem to find a similar situation to this anywhere.

Any advice is appreciated!

-Dan
 

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Dan,
What did you find was the problem? The Porsche dealer replaced the computer under the driver's seat of my 2009 Boxster S after my garage flooded during a storm. Although the water only came within an inch of the door sill water apparently seeped up through openings in the floor. My rear trunk light is not working. I measured 5.46 Volts at the connector.
 
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