C3 fuse keeps blowing

[joecal]

Hello, I'm a new guy here, and just bought a 99 Boxster about a week ago. It's my first Porsche and the car is a lot of fun to drive. The car was fine except for the central locking system and the key fob weren't working. I looked under the drivers seat and took a look at the central locking box under the seat. I really did nothing that I'm aware of, but the central locking system light came on and it started working to my surprise. Today I noticed the windows, interior lights and convertible top aren't working. The C3 15 amp fuse was blown and I replaced it but it keeps blowing the fuse, so I must have a short somewhere. I thought maybe moving the seat forward and backwards might have chafed some wires but I can't see anything wrong from what I can see. Any help is appreciated.

[particlewave]

Check the electrical connectors on the immobilizer for corrosion. You may want to open the immobilizer and check for water damage or corrosion there, also.

[joecal]

Thanks for the reply, I guess the seat has to come out? I looked under the seat and it felt dry, but who knows how the connections look.

[particlewave]

You could unbolt the seat (quick and easy) and just tilt it forward. Make sure to disconnect the battery before unplugging the seat (if you need to) or messing with the immobilizer.

[joecal]

Sounds good, thanks for your help I really appreciate it. I just need to buy the E12 torx socket to unbolt the seat. I'm hoping it's just a bad or corroded connection. I'll post my results in a few days or so.
Joe

[dghii]

disconnect your battery before disconnecting the immobilizer connectors.

[joecal]

Thanks for the tip, I took the seat out yesterday to look at it and again today without removing the seat. It was pretty easy without removing the seat once you've had it out and see how it's mounted. Still no luck though, it did look like it had some water damage underneath the circuit board. I'm taking it to work tomorrow and see if one of the biomed guys can take a look at it, I know nothing about electronics. I'm not even sure if that's the problem, but it's a starting point, the C3 15 amp fuse keeps blowing as soon as I put it in or turn the key in the ignition.

[Sassmatt72]

With the unit unplugged dies it blow the fuze? If so it's in the wiring harness.

[joecal]

I did try that and it doesn't blow the fuse, so it's definitely in the immobilizer. It only blows when the smaller plug with 10 wires or so is plugged in. That appears to be were it had some water damage from the looks of the underside of the board. I tried cleaning it but it didn't help. I'm going to see if a tv repair shop could take a look at it. The one company I found online SECU wants $875.00 to repair one, that's crazy. Thanks for the suggestion.

[joecal]

This is an old thread but it looks like I never posted my findings. What happened was when I replaced the drivers side sun visor I pinched the wiring behind it. The insulation was cut on a few wires, so it was shorting out. It took me a while to figure out what was happening. It was totally my fault, all because of a floppy sun visor. So be careful if you ever take the drivers side visor off to not do what I did. I can't believe I did that, but I'm glad I figured it out by retracing the work I did to the car.

[MWS]

Thanks for wrapping up this thread...many people wouldn't do so. Glad to hear you found and solved your issue.