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Followup To
Question -
Roland,
I have a 1991 Chrysler 5th ave 3.3L. For some reason my Factory alarm system is armed, and will not let me start the car. I know this by the yellow alarm light located on the dashboard, stating its armed. I've disconnected the battery hoping this would rest the computers, but no such luck. My question to is, how can I bybass/Disable this alarm system so I can drive the car again? I would think there would be a way to disable this. Any help would be greatly aprreciated. Thanks Scott
Answer -
Hi Scott,
I suspect that the wiring from the disarm switch at the keylock of the front door (on both sides) has developed an open. That is the only way to diarm an alarmed condition. Try to use the passenger side door lock (lock then unlock with the key) to see if that disarms it. If not, then you might try going to the security alarm module to do that. It is located above the glove box. You have to remove the underdash silencer pad below the glove bos. Then you remove the screws that go around the glove box opening and then the glove box will drop out and you will see a crosswise bracket that holds the module along with the keyless entry module (optional) and the lamp outage module. The theft module is the most inboard on the bracket and has a single 21-pin natural color plug. To get to the plug you will probably have to remove the bracket (3 screws) and also the module from the bracket (2 screws). But DO NOT unplug the module at this time. What you would want to try is to simulate the locking and unlocking of the door at one of the wires from the door lock. These wires are on pins 8 and 15 of the plug (light green/orange and dark green/orange in color). I believe that if you stuck a pin thru the insulation of either wire and then momentarily ground that pin once to a shiney surface of the body structure nearby that it might disarm the system. If not, then ground it momentarily a second time and see if that disarms it. You would know whether it disarms by observing the light on the dash. Doing one momentary ground or two should simulate the action of the door lock.
Once you have disarmed it, you should be able to kill the alarm entirely by unplugging it. BUT, you never want to unplug the alarm UNLESS the engine has been started and is idling when you remove the plug. Otherwise it will push the engine controller into hard lockdown which only a dealer can clear with a diagnostic readout box (DRB II). Also, do not disconnect the battery supply as that will alarm the system also, but not put in a hard lockdown, as far as I know.
You can also verify which part of the system is faulty by running thru this diagnostic routine:
"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 bwtween 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."
So consider these approaches and let me know if it isn't clear. If the diagnostics reveal another area of the system is at fault let me know.
Let me know how it all works out, please.
Roland
Roland,
Thanks for the quick response. Yes, I did try and disarmt he alarm for the passenger door, and nothing happened. So you want me to take the passenger door panel off and and stick a pin thorought he insulation and ground it. I will try this, to see if it works. If this does work the car should start? While the car is running, should I still unplug the alarm module? I did see you tell another person with the same problem, do you know if this cured their problem? It seems like the passenger side is the main source for the alarm to be shut on/off. I'm hoping this will work. If this doesn't work is there anything else that I should try?
I was also told to cut both wires that go tot hat swith in the passenger door. does this make any sense to to? By doing this, will it disable it?
thanks
scott
AnswerHi Scott,
No, I was suggesting that you might go right to the module in the dash and ground/unground either of the front door wires more easily and if it does work then you can get the car running again. But then never use the power door lock switches when you secure the car so the alarm is never set. Or you can decide at that point to remove the plug (but only when the engine is running) and do away with the alarm function (it doesn't cure the problem, it kills the system forever). Or you can try and find the wire breaks between the alarm module and the door key lock switches (probably at the hinge area would be my suggestion)*. The driver and the passenger side are equally capable of disarming. It appears both sides are open on your car.
Cutting both wire will not change anything because they are not connected at this time, that is why it won't disarm. What I suggest you do is go to the module and at the plug pierce one the wires that I described with a straight pin. Then ground and unground the pin once and see if the light goes off and if not, then ground and unground it again.
Roland
*Note that there are actually two wires for each switch in each door: the bi-colored (drive and passenger) that I described and also a black wire that goes to a chassis ground point. So it could also be a ground wire on one side that is open and a multicolored wire on the other side, for example.
