bpayne

OK, I've been searching and tinkering for long enough. I need to ask if anybody can provide any input or perhaps just see it from another perspective.

People do not believe me that the doors are locked and cannot be opened manually, at all.

Recently I grabbed my briefcase out of the passenger seat and locked the doors from the passenger side (not the usual). When I got out of work, the doors were unresponsive. Completely. No sound is emanating from either door, so I know it is not the famous plastic linkage. Both driver and passenger key switches arm or disarm the alarm when turned, as well as turning the interior lights on when "unlocking" or off when "locking".

I suspected the Central Locking/Alarm module. But when I dug it out and put a meter across the pins that drive the lock motors, I see 12 Volts and can hear the relay click, and the polarity reverses when the door key is turned in the opposite direction.

I have continuity to the passenger door harness. The drivers side door harness I cannot get to because of what seems to be an airbag sensor held on with nuts that obviously were designed not to be turned with normal tools. All of my testing has been limited to disconnecting the passenger door harness, checking it directly, and checking the harnesses at the Central Locking /Alarm Module for the drivers side. All with the assumption that wiring to the driver's door is OK.

Here are the results:
1.) The module puts power to the wires correctly, and appears to be operating normally.
2.) The resistance values to the power lock motors are 615K Ohms driver side and 265K Ohms passenger. I'm not sure what to make of the discrepancy yet.
3.) Testing the limit switch at the passenger door harness directly shows it to be grounded, however testing the main central locking plug with the passenger door disconnected (to isolate the driver's door) shows no continuity to ground. So there seems to be a mismatch in what the limit switches are saying about the doors being locked.
4.) Disconnecting the passenger side door harness and applying power to the pins for the lock motor does nothing. Also, applying power to the plug at the module with the passenger door unplugged (to isolate the driver's door) does nothing. This was attempted with both a battery charger and wires directly from the car's battery.
5.) Checking all wires for continuity to ground yields no odd shorts.
6.) Disconnecting the center console switch doesn't help.

I cannot understand why putting power to the correct pins does nothing in either door. I can't believe both motors went bad simultaneously.

Any ideas? I'm open to suggestions.

If not, has anyone ever removed the interior door panels with the doors closed? The Excellence article on repairing power locks cautions strongly against bending them, and the last thing I need is broken interior pieces...on top of getting in and out like the Dukes of Hazzard.

Please let me know if it would be helpful for me to elaborate on any detail.

Thanks,
bp

Riff

I am an electrical idiot, but I do know that there is a microswitch on the barres of both locks. Perhaps you have a malfunction in one that is screwing with the signal??? When I had my door handles apart, I managed to goof up the install of the microswitch causing one side to lack while the other side unlocked. Somehow I fixed it, though I could not tell you exactly how it happened.

Good Luck,

tkacki

Question: Factory alarm or aftermarket ?

Test: Connect back all harnesses and plugs. Remove G19 relay - this is alarm additional relay which also provides signal from door lock module to the alarm module. Open / lock signals from the door lock cylinder switches to the central locking module are ground pulses. Those signals are present in the relay socket. Close signal - upper left small pin (when looking on the socket from above, standing by the fender, fuse banks on your left and bottom). Open signal - lower right small pin. Connect conductivity meeter between ground and close pin. There should be ground present when locking left or right door using key. Repeat with open signal. There should be grounds on pins as long as You hold the key turned. If there is constant ground or no ground, central locking will not work.

If there is no ground - check microswitches on locking cylinders.
If there is constant ground - unplug the central locking module (clipped to steering column) and repeat the test. If OK - central locking module failed. Still ground - check harness.

If test is OK and locking still don't work, remove the central locking module and test motor actuations:
connect 12V and ground between pins 8 and 3 on central locking module socket. You should hear the motors. Reversing polarity should turn motors in opposite direction (lock/unlock). If motors work - replace the central locking module. If not - check harnesses, motors and grounds.

Hope it will help.

bpayne

Thanks guys. I should have been more specific, it is a factory alarm.

Unfortunately, the later car uses a different power lock module than the ones to which you refer. It is a combined unit which controls central locking and the alarm. Different from the one mounted under the steering column. My car has never had a relay in G19.

It is probably more common in a 968 than any 944.

I'm new here, so is there a place I should post that would have a larger population of 968 owners? This forum seemed to make the most sense.

Yes, it blew my mind that applying power to the wires in the door harness going to the motor resulted in...nothing.

Any other ideas or referrals?

Thanks,
bp

tkacki

Looks like newer S2 herness is bit different. Motors could have end-end position switches. How many wires in the motor connector / case ? Try to move motors in the middle position then apply power.

LuisGT3

Just take the rear window out in 7 seconds.

J Berk

Anyone know how this worked out? Same problem I have! Same year car!

bpayne

Well, I've had neither the motivation nor the gonads to attempt removing the door panel for fear of destroying it in the process. My state inspection is coming due soon, so I have to at least attempt to get the doors open for safety reasons. Otherwise I'll be paying out the wazoo for someone else to fix it.

I will post if anything significant occurs.

J Berk

I plan to try taking the panel off with the door closed this weekend...will let you know how I make out.

J Berk

ok....driving myself F'ing NUTS....I got the door panel out with not too much fuss.....the light on my central lock button is ON....but the passenger side door is NOT locked. I can only get this light to momentarily go off...and that's if I am pulling upward on the driver's door lock while pushing the central lock button....so it would appear that the driver's door remains locked no matter what I do.

Now that I've gotten the panel off....can somebody tell me how to manually open the door so at least I can work on this like a human-being??????????????????

Pics would be greatly appreciated

J Berk

bump

nickg

joe ,i have some manuals if you need to use them

bpayne

Well, I ended up having my mechanic take the door panels off. What was inside was somewhat frightening. Both lock motors had been driven for long enough to melt, and subsequently fuse together, the gears inside. The central lock module continues to function normally with the new motors (for now), but I fear that eventually it will happen again. I do have a spare, but for all I know, whatever caused this situation in the first place (relay contacts sticking, I assume) could also be a problem with the used replacement.

Has anyone ever taken one of these things apart to know if the contacts are accessible enough to be cleaned? Part Number 928 618 260.00

Luis de Prat

So, the lock motors themselves can be replaced?

AznDrgn

Yes, they are just little actuators inside the doors. I think I have 2 working ones off an '89 S2 parts car lying around if someone else finds that they need one.