Gazzz999

I have a ’95 993 C2 (ROW, Australia) RHD with Porsche Drive Block System Immobiliser.

I removed and refitted the glove box to clear wiring that had become caught on the end hook of the RH plastic arm (not a new problem - the door has been stiff to operate for a long time). Once the glove box door and compartment were removed I pushed the offending wiring out of the way and secured it with a cable tie, then refitted the glove box.

When I attempted to start the car, I got all normal ignition check lights, including the immobiliser light in the clock. I pressed the immobiliser remote control button and the immobiliser light went out but the motor didn’t crank. I then tried to lock the car with the immobiliser remote control. The red lights on each door flashed as normal, as did the light on the remote, but the car didn’t lock. I am satisfied the remote control is working as I verified the same symptoms with a spare remote. I also tried the central locking button in the center console but no success.

At this stage, I’m assuming the central locking system is not working because I have screwed up something with the glovebox / under dash wiring, as the owner’s manual states the glove box is one of the doors / lids monitored by the alarm system. I’m also assuming it’s not possible to activate the central locking system with any door open, including the glove box door. The manual does state “an Acoustic signal will sound to indicate that the central locking system cannot function due to an open door or a mechanical defect”. I am getting flashing door lights but no acoustic sound (I’ve never heard any “acoustic sounds” since I’ve owned the car).

I checked the glove box light switch and it seems to be working normally as the glove box light illuminates when the door is opened and goes out when the door is closed. I assume the glove box light switch is the same one that activates the immobiliser / alarm system. I’m not aware of any other microswitch in the glove box area that is part of the immobiliser system.

The owner’s manual states “While the immobiliser is activated it is impossible to use the starter”. As that is my major symptom I figure I must get the immobiliser system working before I can start the engine.

Maybe I’m way off track by focusing on the glove box and maybe some of the assumptions I’ve made about the glove box and immobiliser aren’t correct. Confirmation / correction from anyone who knows would be greatly appreciated, together with any suggestions to identify and fix the problem. Throughout this whole exercise the car battery has been connected and I have confirmed it’s fully charged.

Cheers,
Garry

nine9six

Garry,
You are on the right track with the glove box...
What are your door top led lights doing? Fast double blink, or slower single blinks?
Could be your glove box micro switch is out of adjustment, where it operates the light, but not the immoilizer. Also, a ground short in this area will manifest the same symptom.

Gazzz999

Thanks for the response. When I press the remote control, both door LED's blink rapidly. As soon as I stop pressing, the lights go out. Normally, the lights would blink and I would hear the 'clunk' of the doors locking. Now, no clunk. I've got the glove box out again and am poking around in that area but nothing obvious to report.

Gazzz999

The plot thickens … I reassembled the glovebox, satisfied the door switch is working properly. I’m getting 12V across the bulb contacts and the light goes out as the door is closed.

I then checked all the other microswitches in the central locking system. The engine lid switch works well but not the frunk or cabin interior lights. There is no power to the frunk microswitch. Each of the door switches work well - 12V when grounded, but neither of the cabin lights work. The lights are set in position “B” (controlled by door contact) and when set to position “C” (permanently on) they both work so they are getting power, but not via the door switches.

Can anyone tell me if there any other switches / components in the system that might affect power to the frunk microswitch and between the door switches and cabin lights (I have checked fuses)? Or, any other clues where to go from here?

One strange thing I noticed when troubleshooting - when pushing each of the door switches manually, I heard a relay clicking noise that I traced to relay R22, the Power Window Relay (windows work fine). When both doors are open and 1 switch is operated, there is no noise. But when 1 door is closed and the switch of the other is operated, the relay clicks. It’s the same with both doors. Is that normal?

Cheers,
Garry

nine9six

Lets see if memory serves...glove box light, doors/interior lights, engine bay light, frunk light, clutch micro switchs; I believe are all on the same circuit.

Sorry, I cant comment on the normalacy of your door micro switches, but I'd lay odds its the frunk at this point.

There is also a, door open chime relay that needs to be in place; its in front of the drivers left hand, just behind what would be considered the fire wall. I believe you need to pull the snap in plastic piece, that protects the hvac servo units, for access to check its in place and operable.

FWIW, The frunk and engine bay were my culprits to a nonop immobilizer.

Door top leds should rapid blink for a short period, then slow to a 2 or 3 sec single blink. Two blinks indicats an error in the system.

HTH

soin

any chance you could run through the glovebox removal procedure, I'm trying to remove a head unit that i feel maybe secure bolted from the back, was gonna remove the glovebox for access but found only 1 or 2 conflicting diy threads within a search

thanks

Gazzz999

This is the one I followed and found it worked well, although still a total pita to remove plastic arms - lots of fiddling.

https://rennlist.com/forums/993-foru...le-repair.html

I also removed the passenger seat (as I wanted to rejuvenate the leather) and I’m sure that made the job easier in terms of access. Lying on my back and looking up behind the dash, I could see the hooks on the end of the plastic arms and that made removal easier. Good luck.

Gazzz999

Problem solved! After getting nowhere with the door / lid switches I decided to retrace every bit of work I had done on the car in the past week; that had included removing and refitting both seats.

When I removed the RH seat, I found the Alarm Control Unit had become disconnected. I’ve got no idea how that happened; the connector side of the unit is tucked under the seat rail mount and the connector itself is barely visible. No matter, everything is working perfectly now.

Thanks nine9six for your guidance and to other contributors to the various immobiliser threads on this site. All good information.

Cheers,
Garry

Spokes

Amazing, how often the problem is traced to something so simple!

nine9six

Garry, good to hear all is well...