2000 G20 security system issues

[2002sheds]

Hi All,
I am trying to sort out an issue with my MIL's G20. The security system has me stumped. My MIL lost the key fob (remote) a while ago, and she started having issues with the alarm sounding every time she tried to enter the vehicle. She figured out that she could enter the car/disarm the system if she unlatched the trunk first. That worked for about a year. Now she cannot do the "trunk thing"... and every time she opens the door to get in, the horn blares and headlights blink -- the whole thing...
So far, I have downloaded the manual and tried the following:

I tried to disarm the system using the key in the trunk. No change.
I tried to disarm the system by unlocking the car door. No change.
I disconnected the switch in the hood, as advised in some posts. No change.
I Disconnected the 7.5 A fuses #5 and #10. The blinking light no longer comes on, but no other change.
Pulled the relays for the horn and headlights (as they relate to the security system) after the sound of the horn became too much. Obviously, not really a solution...

The car is old in years, but has very few miles (little old lady driver). Any help to solve this issue will be greatly appreciated !!!!


Thanks,
David

[2002sheds]

Okay, an update...I read (here, I think) that you can disarm/rest the security system by opening the trunk with the key (I don't even have the remote anyway) -- be sure to leave the trunk open! -- then get in the driver's seat, close all of the doors and windows, then push the key into the ignition and pull it out SIX TIMES within 10 seconds. The directional lights will flash and you will hear a click, indicating that it worked. And it did !

I then proceeded to replace the various fuses and relays, all the while thinking that the alarm would come on again, but it didn't.

Fingers crossed, this may be all that is needed for now. My MIL is searching for the remote/key fob. If she doesn't find it I will look for one on eBay or elsewhere.

[2002sheds]

Update 2... went out to open the car after it sat for a few hours, and the alarm blared upon opening the driver's door. Tried the key 6 times in and out of the ignition, and this time it did nothing.

Got out of the car, went to the passenger side and unlocked it. The alarm stopped. Unfortunately, my MIL shut the trunk at exactly the same time, so i
I really don't know what caused this to disarm/rest the system. And why did it disarm earlier and then re-arm?

[2002sheds]

Okay...when I unlocked the passenger door, it disarmed the system. I have now found that the driver's door cylinder switch is causing the issue. I can lock but not unlock/disarm from that door.

How do I remove the cylinder?

[Ace2cool]

Most door locks are the same to get to. Remove the door panel, disconnect the latches inside as well as unbolt the door handle, and there is usually a ring clip to hold it in place to the back of the door handle.

[2002sheds]

Hi Ace,
Thanks very much for the reply! Any idea of how to tell if it is indeed the switch by the key cylinder or the "console" with all of the window controls and power locks?

Thanks,
David

[Ace2cool]

I would assume the switch is a simple open/close switch that should be easy to test by a multimeter. Testing the switch would either isolate the problem or point you in the right direction. Hopefully you get it figured out soon! I remember when my driver door lock broke on my TT I was going crazy having to walk around to the passenger side every time.