Chrysler Repair: Theft alarm triggered, wont disarm: 91 5th Ave., remote keyless entry, many different things


Question
Roland,

I'm having a heck of time trying to get my 91 Fifth Ave 3.3L running.  the alarm is set, and I cannot start the car.  I've tried many different things to de-activate the alrm but nothing seems to work.  I've tried the keys in the door, disconnecting th battery, but nothing works.  The light on the dash  stays lit, and the car will just crank as of the car fuel pump is shut down.  There has to be a way to de-activate this alarm to get the car running.  Can you give me some ideas what I could do? Any help would really be appeciated.

Scott

Answer
Hi Scott,
I get this question regularly and I'm trying to get a handle on the answer, so let me know how this gets resolved for you, please.
It should disarm by using the key to lock/unlock either front door. Another way to disarm is using the remote keyless entry if there is one for the car, and that is a more 'active' disarm.
If those do not bring success I would try do the self-diagnostic test on the unit:
A diagnostic mode is available in the system to verify operation of all monitored switches or circuits. To enter diagnostics, cycle the ignition key to the accessory position 3 times, leaving the key in this position.
Upon entering diagnositics, the park and tail lamps will begin flashing to verify their operation. In addition, the horn will sound twice to indicate that the trunk key cylinder is in its proper position. Returning the ignition to the OFF position will stop the lamps from flashing while keeping the system in diagnostics.
While in diagnostics mode, a horn pulse should occur at each of the following events indicating proper operation:
(1) Beginning with all doors closed, open then close each door. The horn will sound when the door ajar switch closes, and then again when the switch opens. There must be a 1 second delay between closing and opening the switch.
(2) Open, then close the hood. The horn will sound when the hood is opened, and again when it is closed.
(3) Activate the power door locks in both the lock and unlock directions. The horn will sound after each activation.
(4) Rotate the key in each of the door lock cylinders to the unlock position. The horn will sound as the switch closes, and again when it opens. There must be a 1 second delay between changing switch states, or the horn will not sound.
(5) Cycle the key to the ignition RUN position. A single horn pulse will indicate proper operation of the ignition input. This will also take the module out of diagnostics mode. For any of these tests, if the switch does not remain open or closed for at least 1 second, the horn will only sound once.
The lack of a horn pulse, during any operation, indicates a switch failure, the lack of that input in the Vehicle Theft Security system module, or a failure internal to the module. Check for continuity at the switch, if this is good, check for an open or shorted wire between the switch and the alarm module. This self-diagnostic test may reveal component failure that is preventing the disarming, and once you correct that, you should be able to disarm the system.
I am expecting to receive a manual for the body systems of the '92 New Yorker that I just purchased on eBay so I might learn something more from that. I do have a manual for the 93-4 Security System but so far I haven't found where it mentions what to do specifically about a failure to disarm.
It makes use of the DRB II diagnostic unit, which I do own, but my '89 LeBaron doesn't have such a system so I haven't had an oppotunity to troubleshoot the theft system with that tool. When I get the '92 manual I'll see if it addresses the theft system and its frailities. I would be willing to lend you the DRB II (with a security deposit), but without the correct manual it won't be helpful.
I wonder if you tried to disconnect the battery  and then try the door locks/keyless entry again whether you might be successful. I have the impression though that if by chance there was an attempt to unplug the security module with the engine NOT running at the time, then the system goes into a deeper lockdown that may require the DRB to intervene.
So those are my present thoughts. I would be pleased to learn of your progress, and I will let you know once I get the '92 manual.
Roland