merchauser

just learned in another thread that 1991 cars were factory upgraded to allow lock function of doors in tandem with rear deck key lock.
is there a way to upgrade my 1990 rear deck lock to allow for this feature?

ROG100

1990 to 1995 have that feature. So your car has this feature already.
If the key in the door will close the windows and sunroof the same applies to the trunk. If someone change the hatch lock to none alarm then that deletes the feature at the hatch.
The brain is located under the drivers seat (left seat).

ROG100

I looked at both the 90 & 91 Service info bulletins.
In 91 they added a new alarm system with the control unit under the right seat.
For 90 they state that the windows and sunroof can be closed using the key function on both doors but does not say the trunk.
For 91 no specific detail about the function being added to the trunk but reading the additional alarm functions this could indeed be the case.
So it possible that the function via the trunk was a 91 addition via the new alarm system.

Alan

Yes it is related to the new alarm system under the passenger seat. The window roll-up from the locking mode is implemented on the window controller under the drivers seat (90+ models only) - but this only worked from the door locks until the later alarm unit was added in '91 models

This new alarm also adds new sensor input possibilities (Porsche never used them), alarm diagnostics via Bosch hammer, hatch alarm suspend mode, locking from hatch (incl. windows roll-up) - more too.

Alan

merchauser

I am able to lock doors and roll up windows with trunk lock key, but not able to unlock. would be nice to add

Alan

A '91 doesn't do that, it locks but doesn't unlock the doors - that is where the suspend mode comes in. When you open the hatch - the alarm goes into suspend mode - it resumes full operations as soon as you close the hatch. No need to disarm/unlock (all) or re-arm/re-lock (all) to get something out of the trunk.

Makes sense.

Alan

merchauser

my mistake. did the later cars (GTS) have unlock ability for the doors from the hatch lock key?

Simon928

This isn't a direct answer to your question, but if you ever wanted to completely bypass the need to use your keys to lock or unlock your doors I made a noob level set of instructions for keyless entry on a 1990.

https://rennlist.com/forums/928-foru...l#post14013315

Alan

No - GTS cars are the same in this respect as the 1991 models. Not sure why you'd want to unlock the doors from the hatch lock?

I have an aftermarket Keyless Entry - you can unlock/disarm and lock/arm from anywhere in a reasonable range - 2 clicks on the unlock button opens the trunk,
holding down lock closes the windows. Features depend on the model you choose and your install choices - but all very doable.

I think this is the ideal solution - I very rarely use the key in the trunk lock (or in the doors for that matter). Recommended!

Alan