Description and operation

Central timer module

Two versions of the Central Timer Module (CTM) are available on this vehicle, a base version and a high-line version. The base version of the CTM is used on base models of the vehicle. The base version of the CTM combines the functions of a chime/buzzer module, an intermittent wipe module and an illuminated entry module into a single unit. The base CTM also uses inputs from the door ajar switches, the headlamp switch and the key-in ignition switch to control the output to the dome lamp circuits, which allows the base CTM to provide load shedding to help protect the battery from becoming discharged.

The high-line version of the CTM is used on highline vehicles. The high-line CTM provides all of the functions of the base version CTM, but also is used to control and integrate many of the additional electronic functions and features included on the highline models. The high-line version of the CTM contains a central processing unit and interfaces with other modules in the vehicle on the Chrysler Collision Detection (CCD) data bus network.

The CCD data bus network allows the sharing of sensor information. This helps to reduce wire harness complexity, reduce internal controller hardware, and reduce component sensor current loads. At the same time, this system provides increased reliability, enhanced diagnostics, and allows the addition of many new feature capabilities.

One of the features that the high-line CTM supports and controls is the Vehicle Theft Security System (VTSS). In the VTSS, the CTM receives hardwired inputs from the door and liftgate ajar, door and liftgate lock cylinder, and ignition switches. The programming in the CTM allows it to process the information from these inputs and send control outputs to energize or de-energize the headlamp (or security) relay, horn relay, and the security lamp. The CTM also sends CCD data bus messages to the Powertrain Control Module (PCM) to control the engine no-run feature of the VTSS The high-line CTM also contains the receiver and control logic for the power lock and Remote Keyless Entry (RKE) systems, which are integrated into the arming, disarming, and triggering functions of the VTSS.

Both versions of the CTM are mounted under the passenger side end of the instrument panel, outboard of the instrument panel glove box opening. Refer to Central Timer Module in the Removal and Installa- tion section of Group 8E - Instrument Panel Systems for the service procedures.

For diagnosis of the high-line version of the CTM or of the CCD data bus, a DRB scan tool and the proper Diagnostic Procedures manual are recommended.

The CTM cannot be repaired and, if faulty or damaged, it must be replaced.

Door ajar switch

The door ajar switches are integral to the door latches on each door. The switches close a path to ground for the Central Timer Module (CTM) when a door is opened, and open the ground path when a door is closed.

The door ajar switches cannot be repaired and, if faulty or damaged, the door latch unit must be replaced.

Liftgate ajar switch

The liftgate ajar switch is integral to the latch on the liftgate. The switch closes a path to ground for the Central Timer Module (CTM) when the liftgate is opened, and opens the ground path when the liftgate is closed.

The liftgate ajar switch cannot be repaired and, if faulty or damaged, the liftgate latch unit must be replaced.

Door lock cylinder switch

DESCRIPTION

The door lock cylinder switches are mounted to the back of the key lock cylinder inside each front door.

They are resistor multiplexed momentary switches that are hard wired between a body ground and the Central Timer Module (CTM) through the front door wire harnesses. These switches are driven by the key lock cylinders and contain three internal resistors.

One resistor is used for the neutral switch position, one for the lock position and one for the unlock position.

The door lock cylinder switches cannot be adjusted or repaired and, if faulty or damaged, they must be replaced. For complete circuit diagrams, refer to Vehicle Theft Security System in the Contents of Group 8W - Wiring Diagrams.

OPERATION

The door lock cylinder switches are actuated by the key lock cylinder when the key is inserted in the lock cylinder and turned to the lock or unlock positions.

The door lock cylinder switch closes a path to ground through one of three internal resistors for the CTM when the front door key lock cylinder is in the lock, unlock or neutral positions. The CTM reads the switch status through an internal pull-up, then uses this input and its internal programming to control the proper Vehicle Theft Security System (VTSS) and power lock system outputs.

Liftgate lock cylinder switch

DESCRIPTION

The liftgate lock cylinder switch is mounted to the back of the liftgate key lock cylinder inside the liftgate.

It is a resistor multiplexed momentary switch that is hard wired between a body ground and the Central Timer Module (CTM) through the liftgate wire harness. This switch is driven by the key lock cylinder and contains three internal resistors. One resistor is used for the neutral switch position, one for the lock position and one for the unlock position.

The liftgate lock cylinder switch cannot be adjusted or repaired and, if faulty or damaged, it must be replaced. For complete circuit diagrams, refer to Vehicle Theft Security System in the Contents of Group 8W - Wiring Diagrams.

OPERATION

The liftgate lock cylinder switch is actuated by the key lock cylinder when the key is inserted in the lock cylinder and turned to the lock or unlock positions.

The liftgate lock cylinder switch closes a path to ground through one of three internal resistors for the CTM when the liftgate key lock cylinder is in the lock, unlock or neutral positions. The CTM reads the switch status through an internal pull-up, then uses this input and its internal programming to control the proper Vehicle Theft Security System (VTSS) and power lock system outputs.

Headlamp relay

The headlamp (or security) relay is a International Standards Organization (ISO) micro-relay. The terminal designations and functions are the same as a conventional ISO relay. However, the micro-relay terminal orientation (or footprint) is different, current capacity is lower, and the relay case dimensions are smaller than those of the conventional ISO relay.

The headlamp relay is a electromechanical device that switches battery current to the headlamps when the high-line Central Timer Module (CTM) grounds the relay coil. See Headlamp Relay in the Diagnosis and Testing section of this group for more information.

The headlamp relay is located in the Power Distribution Center (PDC), behind the battery on the left side of the engine compartment.

The headlamp relay cannot be repaired and, if faulty or damaged, it must be replaced.

Horn relay

The horn relay is a International Standards Organization (ISO) micro-relay. The terminal designations and functions are the same as a conventional ISO relay. However, the micro-relay terminal orientation (or footprint) is different, current capacity is lower, and the relay case dimensions are smaller than those of the conventional ISO relay.

The horn relay is a electromechanical device that switches battery current to the horn when the horn switch or the high-line Central Timer Module (CTM) grounds the relay coil. Refer to Relays in the Diagnosis and Testing section of this group for more information.

The horn relay is located in the Junction Block (JB), on the left end of the instrument panel in the passenger compartment. See the fuse and relay layout label on the inside of the fuse access panel for relay identification and location.

If a problem is encountered with a continuously sounding horn, it can usually be quickly resolved by removing the horn relay from the JB until further diagnosis is completed.

The horn relay cannot be repaired and, if faulty or damaged, it must be replaced.

Security lamp

The security lamp is located within the instrument cluster on the instrument panel. The security lamp is illuminated by a red Light-Emitting Diode (LED) that is integral to the instrument cluster circuit board. The security lamp receives fused battery feed at all times and is grounded by the high-line Central Timer Module (CTM) to give a visual indication of the Vehicle Theft Security System (VTSS) arming status.

The security lamp cannot be repaired and, if faulty or damaged, the instrument cluster unit must be replaced. Refer to Instrument Cluster in the Removal and Installation section of Group 8E - Instrument Panel Systems for the service procedures.