I have a 2001 996, original owner, no water issues, parts are all original. Car sits unlocked in garage. Recently starting getting a double horn signal every now and then. Would also hear locks buzz every now and then on their own. Also noticed the frunk light going on and off on its own at some stage.
Read codes using Durametric and am seeing:
61 - central locking limit position unlock not reach
Status: Present
Occurrence Counter:24
47 - central locking synchronization
Status: not present
Occurrence counter: 15
When this problem started, I noticed that the passenger door would not lock (using key in driver’s door including using the emergency locking operation of turning key to lock position 3 times in succession or a single turn) or using the fob. Both driver and passenger window would drop fine when using the relevant door handles. Battery is fully charged. Car runs fine. No blown fuses.
So reading all the posts about failing microswitches, I removed the passenger side lock assembly which is what I originally suspected to be the problem. Took it apart and redid all solder connections on the PCB and then did a temporary reconnect of just the electrical side of the lock module with the cover open so I could see what was going on with it and why I would only hear a buzzing sound rather than the definitive click from the passenger lock. The passenger lock assembly just has 2 microswitches (one outside the assembly to tell if door is closed and the other inside that gets actuated by a white plastic ramp that is driven by the single motor).
The buzzing sound was because the motor would turn but the black clutch type mechanism would not turn and hence the lock would not change position. See attached video. The sound that the locks make can also be heard here.
So I tried applying about 3VDC to pins 1 and 2 on the removed passenger door lock using a bench power supply and I could get it to work just fine and change directions. Both microswitches tested just fine and were clean.
Somewhere along the way of all of this troubleshooting, the driver side door lock started doing the same thing and making the same sound. I have not taken this apart as I am guessing it is perhaps the same situation as the passenger one that I have removed.
I have removed the central locking switch and that tested ok. I have tested continuity across the frunk microswitch by disconnecting the connector in the frunk and manually closing and opening the latch using a screwdriver while checking continuity and it works fine. Reason I was looking into this as one other weirdness that started at around the same time is the frunk light (original non LED and bulb is ok) would come on and go off on its own and now does not come on at all. It has +12VDC going to it but the - is not happening which happens through the alarm module I believe. I do have the alarm horn disconnected currently as I got tired of hearing the double horn signal and hopefully that is not causing any of these issues.
The gas cap locking pin also does not not move. I tried manually pulling and retracting it and it moves manually like that but not when locking or unlocking.
Also removed the alarm module from under the driver’s seat. The fuse was fine and both sides of the PCB visually looked ok.
So my questions are:
-Could both my locks have failed one right after the other where the lock motors are not working properly and that is the only problem?
-Or is there something in the alarm module that has failed? The weirdness with the frunk light along with the locks not working despite microswitches being okay is making me wonder if it is indeed the alarm module.
-Anything else I can try to narrow this down?
Thanks.
IMG_2465.mov