avslash

Working to sort out the new Cab, and I noticed the immobilizer is giving the "double blink" code when engaged.

After searching the archives, I was able to narrow the trouble down to the glove box door.

When the immobilizer is engaged with the glove box door closed, the LED's give the double blink.

When the immobilizer is engaged with the glove box door open, the LED's give the standard one blink per 2-3 seconds.

This seems counterintuitive to me. Seems the trouble code would come up when the glove box was open, and not vice versa. The glove box switch does turn the light on/off, so it has at least some level of funtion.

Any advice from the hive mind. Any knowledge on how difficult the glove box switch is to replace??


Second question relates to the night time illumination for the console switches. Two of these bulbs look to be burnt out in my car. Anyone know the wattage bulb the need to be replaced with. They appear to be solder in place, but I assume they can be replaced via desoldering and dropping in some new ones.

Thanks for any ideas.



UPDATE:

So after a little disassembly and experimentation. Here is what I found.

When the glove box courtesy lamp bulb is removed, the "trouble blink code" disappears, and all is normal, regardless of switch position.

When the bulb is in place and the door is open, all is normal.

I could really use a pointer from someone familiar with troubleshooting this. I'm out of ideas as to what this is telling me.

Thanks.

avslash

Bump for one more shot at some ideas.

NC TRACKRAT

O.K, I'll take a stab at it. Yes, the switch turns the light off but are you sure it goes off AFTER you've closed the glove compartment door? (check the current draw on the circuit) If it does go out, then you may have a wire in the light switch circuit that's grounded somewhere. When you pull the bulb, it's acting like a switch.

avslash

Good thought on whether or not the bulb is actually off when the door is closed.

How best to check?? Pull fuse and check current draw with multimeter at fuse block w/ glove box door open and light on and then with door closed and light presumably off??

For that matter, I guess I should check current draw on that circuit w/ bulb present and non present. Difference in draw w/ bulb not present would indicate short to ground.

THanks, now I have something to check. Off to try and find a wiring diagram.

944/951guy

Great topic. I want to know what happens. My car double blinks too but i dont know where the problem is.

Bouzoukikid

It would be easy to tell if the bulb does not go out as it would be extremely hot. Not sure, but the switch may have a double function ie two sends, one to the glovebox and another to whatever is causing the problem. That's a guess though.

avslash

I think this must be correct based on what I am seeing.

If the bulb is out of the holder, the system arms and behaves normally at all times.

If the bulb is in and the glove box switch is open/on with the bulb illuminated, the system arms and behaves normally. I believe this is correct operation w/ the system sensing the open/on switch and ignoring that input when arming the system. Further evidence that this is normal operation is that if the status on this zone changes while the system is armed (close the switch) an alarm is triggered.

If the bulb is in and I manually depress the glove box switch (glove box door open, so I can verify the light is out) the system gives the trouble code blink when armed.

I think the proper inference from all of this is that a low current that is insufficient to illuminate the bulb must be passing through the bulb circuit to ground when the switch is closed and triggering the alarm fault. As no fault is triggered without the bulb in place. The fault must lie on the downstream/load side of the bulb. As opening the glove box switch does not provide proper operation with the bulb in place, there must be a path to ground on the hot side of the glove box switch.

Got to track down a diagram. Maybe Alldata at the local library has it.

tonypai

I'm curious about this as well.

My immobilizer light never comes on (it's not the bulb) and fuse #11 (glove box/trunk light) is currently overloaded. Whenever I put in a fuse it immediately pops.

Other than that the immobilizer works fine. But I would like to get the immobilizer light working so I can program a spare remote.

I have a feeling it has to do with the aftermarket stereo I installed but it sounds like everything is interrelated. Interested to see what others have found.

davesnothere

Are you sure that this is the right bulb for the glovebox, i.e. wattage? I'm wondering if the wrong replacement bulb, with a higher wattage, might yield more or less of a current drop when switching from on to off (this assumes that the immobilizer is looking at current drop, and not just current presence or absence).

I'm interested to see how this one plays out as well. I love a good puzzle...

- Dave

Bouzoukikid

This does make sense but I think if the bulb is not glowing then it is more likely that it acts like a fuse (either on or off), but it could be that the alarm is extremely sensitive in which case its worth a try.

I have an appointment with "Hamilton and Parker" on Tuesday to have my immobiliser board replaced and buy new remotes, and I'm going to ask them on their thoughts on the cause. They're the original installers for porsche uk, I'm sure they'll know. But maybe UK alarms are slightly different to the original installation?
Love a puzzle also.
Costa.

avslash

I love a good puzzle, as well. Since I have no idea of the provenance of the actual bulb installed, I might just try and drop by the local stealer (love that term that I picked up here) and get an OEM one, just to make sure.

If Hamilton and Parker have any insight on the wiring schematic you can share, that would be very helpful. There are "doubled" wires on the hot side of both the lamp holder, and the switch. this supported my theory on the location of the path to ground above.

I'll report back after the bulb swap.

avslash

Well, after acquiring a legible wiring schematic and finding a little time, the solution presented itself in short order.

Whoever tinkered underneath the dash prior to my ownership had reversed the connections between the glove box lamp holder and the glove box lamp switch. Seems like that would be easy enough to do if you mistakenly thought you had to pull the whole glovebox liner out to swap a burned out bulb.

From the schematic, it looks like the immobilizer must receive some sort of voltage input through the bulb whether it is on or off. I presume it must have a hi/lo logic built into it that it uses to determine whether the glove box "zone" is open or closed when arming.

Anyway, in my case, swapped the wiring terminations back as per the schematic and my "double blink" is history.

1pcarnut

Great sleuthing, thanks for the solution. Always good to save those little tips in the back of the mind. Course, by the time I need it, I won't remember!

davesnothere

Excellent! Having disassembled my glove box a few times, it didn't seem that the polarity of the bulb holder connections mattered (i.e. you could put the connectors on either terminal), but clearly it does. Guess I just got lucky when reassembling.

Good to know! Thanks for sharing your results,

- Dave

Bouzoukikid

Well done. Nice to see you worked it out. Satisfying when a solution is found with no or little expense. Unfortunatley I wasn't so lucky yesterday. Complete new system required