1999 996 won't start C3 fuse blown

[Ckroeger]

Hi,
1999 Porsche 911 (996) Cab - Automatic Trans., Aftermarket Alpine Radio
I'm trying to track down a bad alarm switch (I think). Following are the symptoms:
1. Alarm double beep when activating
2. Door Locks and Windows don't work (15 AMP Fuse C3 blown)
3. Battery is fully Charged 
4. I disconnected the ignition switch, reconnected the battery and fuse still blows
5. I disconnected the door lock switch and fuse still blows
6. I disconnected the overhead light array and the fuse still blows
7. Car (basically) does not start (fuel pump works). Car will start intermittently, but maybe 10% of the time trying
8. I replaced the ignition relay (old one was working but showing some resistance on the ohm meter)
9. Problem surfaced when I stopped for gas, filled the tank and the car wouldn't start. I realize there's a lock on the gas cover...have not done troubleshooting on it as I think I have to remove the wheel well to get to it.
10. If I had a wiring diagram, it would make things a whole lot easier!!!
11. I connected a scanner...no faults...I got a green light...however, the scanner does not check the alarm codes
Any help would be appreciated.
Thank you

[Loren]

 

Alarm two beeps means there is an alarm fault. And... C3 is the alarm fuse.

Did you have any water get in the car?  Especially under the driver's seat - where the alarm and central locking control unit is.

If you did, then the alarm unit will need to be removed cleaned and dried out. Even then if there is corrosion then you may need a replacement.

[Ckroeger]

Hi Loren,

Thank you for the advice.  The car is dry...but I'll take your advice and check it anyway.  I can smell the electrical burn in the car but haven't found the short yet.  I'll report back.

[Ckroeger]

Hi Loren,

just an update...I was wrong!  The floor is soaking wet behind both the drivers and passengers seats.  I didn't notice it because I didn't look there...duh.

anyway...now I'm certain that you're correct.  I'll report back!

[Loren]

This would also be a good to time to clear your drains. Do a search here as cleaning drains has been covered many times.

[wildbilly32]

Loren: Does a Cab have roof drains similar to a Coupe?

[Loren]

5 minutes ago, wildbilly32 said:

Loren: Does a Cab have roof drains similar to a Coupe?

 

Yes.

 

[Ckroeger]

Loren...you were right all the way...but so much for my luck.  The board is fried!  The part number is 996.618.260.07  Can these be repaired?  If so, who repairs them?  I am assuming that if I replace it, it'll need to be programmed to the key?  Is there a way to override this system?

 

[Loren]

I do not see an exchange part available from Porsche. Sorry.

 

It looks like an MSRP $507.26 for the control unit.

There will be at least one hour of programming to program the new module to your car. That will need to be done by a shop with a PST2 (or PIWIS) and will require your IPAS codes. Of course a dealer/OPC can also do this.

 

If a third party shop does this programming then you will need to go to a dealer and request your car's IPAS codes printout. Most dealers will require proof of ownership before doing that. And they should not charge you for the printout.

[Ckroeger]

Got it...Working on that now.  Moving on to the drains...will report back.

[Ckroeger]

OK, so I cleaned the drains...it was the 2 in front that were clogged.  That said, I found a tube that was disconnected (see pics) but could not find where to connect it to...any idea where the tube goes?

[Loren]

Battery vent.

It should be connected to the vent on your battery. The battery seller should have provided a vent kit for you battery to adapt it their battery.

[Randoe]

Thank you Loren, I've wondered about that hose was for. And I installed a window regulator two weeks ago and wasn't hard at all. I used the you tube video to help me. And have that working well. Just still having problems with car staying in running position. Not having any luck there. I enjoy reading everything and will help anyone with anything I know. 

 

 

Randoe K

[Loren]

7 hours ago, Randoe said:

Thank you Loren, I've wondered about that hose was for. And I installed a window regulator two weeks ago and wasn't hard at all. I used the you tube video to help me. And have that working well. Just still having problems with car staying in running position. Not having any luck there. I enjoy reading everything and will help anyone with anything I know. 

Randoe K

 

Scan the car for Porsche fault codes.