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Questions and Answers

Jeep Grand Cherokee Security Light On

Q. I have a 1994 Jeep Grand Cherokee Limited; 318 V-8; and 134,000 miles. Here is my question/problem. The Security idiot light on the dash panel is on all the time. The security system seems to be working ok, just that the light will not go off. We live in a rural area, so the security system is not a high concern of mine.

Jeep Grand Cherokee Security Light On

In other words, I don't care if works or not, I just can't stand that light being on. Any help would be appreciated. I read somewhere that maybe reprogramming my keyless entry units might help, so I did that, but now the drivers side door will not work with the electric locks. But that is another problem.

Thank you,
Mark

A. Chances are it's a bad door or hood switch keeping the light on. The system is easy enough to test without any special tools. A diagnostics mode is available in the system to verify operation of all monitored switches or circuits.

To enter diagnostics without the DRB, cycle the ignition key to the accessory position three times, leaving the key in this position.

Upon entering diagnostics, the headlamps, park, and tail lamps will begin flashing to verify their operation. In addition, the horn will sound twice. Returning the ignition to the OFF position will stop the lamps from flashing while keeping the system in diagnostics.

Jeep Grand Cherokee Security Light On

While in diagnostics mode, a horn pulse should occur at each of the following events, which indicates proper operation. (Note that some vehicles equipped with the Vehicle Theft Security System are also equipped with illuminated entry (see chart). When in diagnostic mode, it is recommended that the illuminated entry relay be removed. Otherwise it is necessary to wait for the 30 seconds delay after each door opening or closure.)

  1. Beginning with all doors closed, open, then close each door. The horn will sound when the door jamb/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 (except Viper).
  4. Rotate the key in each door lock cylinder to the unlock position (except Viper). 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. Activate the remote keyless entry in both the lock and unlock directions. The horn will sound after each activation.
  6. Cycle the key to the ignition RUN position. A single horn pulse will indicate proper operation of the ignition input. This also will take the module out of the 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 either:

  • A switch failure
  • The lack of that input to the Vehicle Theft Security System module
  • 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 alarm module. Also, check if the Powertrain Control Module (PCM) has been replaced recently. For the first 20 engine starts with a new PCM, the Vehicle Theft Security System will function normally except it will not prevent the engine from running.

NOTE: A PCM from a vehicle equipped with a Vehicle Theft Security System (VTSS) cannot be used in a vehicle that is not equipped with a Vehicle Theft Security System.

If the VTSS indicator lamp comes on and stays on after the ignition has been placed in the ON position, the CCD bus communication with the powertrain control module possibly has been lost.

As a last resort you can always remove the bulb from the instrument cluster.

Additional Information provided courtesy of ALLDATA

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© 2003 Vincent T. Ciulla

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