Expert: Roland Finston - 10/22/2011

Question
QUESTION: My 91 Imperial has always had problems reseting the alarm and ignition disabler with the key in the door locks. I have always waited for the alarm to cycle until it quits and then enter self diagnostic mode and it has always reset that way. A few days ago the alarm was set using the passenger side lock button and now I can't get the system to enter self test mode or reset.  The engine will not start and I have removed two of the three modules from the car which I found out was a no no!  Can you guide me in the right direction.

ANSWER: Hi Larry,
If you removed the theft module above the glove box that may have put you into a harder lock out than in the past. My suggestion would be to reassemble everything and then go to that security module which has 21 pins. Then ground either the wire on pin 8 light green/orange or on pin 15 dark green/orange momentarily which is what the use of the door key does to disarm the system.
A nearby ground point would be the wire on pin 1. Just expose a bit of the insulation to make the jump between the pins or probe into the plug pin/wire interfaces to make a brief grounding action. Then see if that has disarmed it. If not, then it sounds like you may have to speak to a dealer about interfacing with the DRB II device to remove the 'hard' shut down. One other try would be to lock either door with the key, then do the same jump which I described above.  
Roland

---------- FOLLOW-UP ----------

QUESTION: Roland, that suggestion worked 100% fine, but I have a question, do the door lock switches fail often on these cars?  I never had a key fob remote with this car and am considering buying one on line.  The alarm system always used to disarm simply by unlocking the door with the key, then it would only work on really warm days but not on cold days, and finally doesn't work at all.  Are replacment door switches available if there isn't some other fix you can recommend?  Thanks, Larry.

Answer
I am not sure if it is the door lock switch that has failed or the wire between the switch and the theft module which of course flexes at the hinge area and thus is subject to failure. There is a 6-pin disconnect at the hinge (I am not certain if it is in the door, in the opening, or in the cabin next to the hinge area) and  but could check the dark green/orange wire on the right side and the light green/orange on the left side at the disconnect to see if the problem is between the lock and the disconnect (the lock side should short to ground) or the disconnect to the theft module (to pins 8 and 15) using an ohmmeter to check for continuity as you cycle the door lock/flex the wires. Only a dealer part counter would know about the part replacement availability.
Roland