Part 3 of 3

MANUAL A/C (HVAC)/REAR WINDOW DEFOGGER
The Prowler comes standard with manual air-conditioning. The actuators for blend-air and fresh/recirc are cable operated. The mode door is electrically activated by the BCM based on input from the HVAC control head. The BCM uses an electronic cycling switch to prevent evaporator freeze-up.

When the ignition is in the "run" position, the body control (BCM) monitors the electronic cycling switch state and the status of the A/C switch. Based on this information, the BCM sends a CCD message to the powertrain control module (PCM) indicating the A/C switch status and the electronic cycling switch state.

The body control module controls the mode door position by receiving different voltage levels from the HVAC control over the A/C mode switch MUX circuit. Included in this signal is the input for the rear window defogger. The Rear Window Defogger button is located in the center of the Mode Control knob. Press this button once to turn ON the Rear Window Defogger and a second time to turn it OFF. A LED in the button shows that the defogger is ON. The defogger turns OFF automatically after 10 minutes of operation. Each later activation will allow 5 minutes of operation. The timer functions for the rear window defogger are controlled by the BCM.

POWER DOOR LOCKS
Power door locks are standard equipment on all Prowler vehicles and have the following features:
- Automatic door locks - automatically lock the doors when all doors are closed and the vehicle reaches a speed of 18 mph. This feature can be enabled/disabled by the DRBIII(R) or by the customer cycling the ignition key from "OFF to Run" four times (leaving the key in the OFF position) then pressing any power "lock" switch and removing the key from the ignition switch. A single chime will signal programming completed.
- Power door lock inhibit feature - cancels lock switch actuation when the key is in the ignition and either door is open.
- To prevent motor burnout, the BCM will pulse the lock/unlock relays a maximum of 4 seconds. Even though the switch may be held down longer.
- This vehicle is NOT equipped with central locking (unlocking one door with the key opens both doors). However, the vehicle is equipped with door key cylinder switches that are used exclusively for the vehicle theft security system and will arm or disarm the system.

Remote Keyless Entry (RKE) (standard Equipment)
The body control module interfaces with the remote keyless entry module via a one-way serial bus interface. The RKE module is located under the left side of the instrument panel top cover. It does not actuate relays directly but receives the signal from the transmitter and then communicates with the BCM.

Two transmitters are provided with each vehicle, but the RKE module is capable of accommodating four transmitters. The transmitters can be programmed by using the DRBIII(R) or the customer can add a transmitter providing a valid previously programmed transmitter exists. This is accomplished by pressing and holding the programmed transmitter unlock button from 4 to 10 seconds and then while still pressing the unlock button, press and release the panic button. This will put the BCM in programming mode. The customer will have approximately 30 seconds to press any button on each transmitter thereby programming that transmitter to the receiver. A technician with the DRBIII(R) can reprogram any RKE module providing VTSS is disarmed.

The RKE system, operated by the transmitter, has three modes of operation controlled by three buttons.
- Unlock button: Pressing the unlock button once will unlock the driver's door, disarm VTSS and illuminate the interior lamps. Pressing the unlock button twice within 5 seconds unlocks both doors.
- Lock button: Pressing the lock button locks all doors and sounds the horn once (if horn chirp is enabled).
- Panic button: When the panic button is pressed the horn is pulsed, the headlamps and marker lamps are flashed and the interior lamps are turned ON. This will last for up to 3 minutes or until the panic button is pressed again or the ignition is turned ON. The panic feature only works when the ignition is in the OFF position.

*Horn chirp: When all doors are closed and a lock command is sent by the RKE transmitter, a horn chirp will be heard. The horn chirp is also customer programmable by pressing and holding the lock button on the transmitter for 5 seconds and then while still holding the lock button, pressing the unlock button and releasing both. This will toggle (enable/disable) the horn chirp.

VEHICLE COMMUNICATION
The Chrysler Collision Detection multiplex system (CCD bus) consists of a twisted pair of wires. These wires run from one module to another. They receive and deliver coded information between the modules. The information is coded to identify the message as well as the importance of the message. When there are multiple messages trying to access the CCD bus at one time, the code determines the message that has higher priority, which is then allowed to access the bus first.

The two wires of the twisted pair that make up the CCD multiplex system are called "bus +" (bus plus) and "bus-" (bus minus) respectively. Each wire has a measurable voltage level of roughly 2.5 volts. In order to maintain the 2.5 volts on each line and provide a means of transportation for the coded messages, there is a "voltage divider network". This network consists of some modules with bias and some with termination. Bias is the part of the voltage divider network that places both bus + and bus - at 2.5 volts. Termination in the circuitry is required to complete the voltage divider network and also provides some electromagnetic protection for the bus.

NOTE: COMMUNICATION OVER THE BUS IS ESSENTIAL TO THE PROPER OPERATION OF THE VEHICLE'S ON-BOARD DIAGNOSTIC SYSTEMS AND THE DRBIII(R). PROBLEMS WITH THE OPERATION OF THE BUS OR DRBIII(R) MUST BE CORRECTED BEFORE PROCEEDING WITH DIAGNOSTIC TESTING. IF THERE IS A PROBLEM, REFER TO THE VEHICLE COMMUNICATIONS.

Bus Failure Messages

Short to Battery - Either or both of the bus wires are shorted to the battery potential or a specific ground may be open.

Short to 5 Volts - Either or both of the bus wires are shorted to a 5-volt potential.

Short to Ground - Either or both of the bus wires are shorted to ground.

Bus (+) & Bus (-) Shorted Together - The two bus wires are shorted together.

No Termination - The bus system has lost connection with all of its terminators.

Bus Bias Level Too Low - Either or both of the bus wire potentials are significantly below their normal 2.5 volts.

Bus Bias Level Too High - Either or both of the bus wire potentials are significantly above their normal 2.5 volts.

No Bus Bias - The bus system has lost connection with termination and/or bias.

Bus (+) Open - The bus (+) wire has lost connection with termination and/or bias.

Bus (-) Open - The bus (-) wire has lost connection with termination and/or bias.

Not Receiving Bus Messages Correctly - The DRBIII(R) cannot communicate over the bus and does not know why.

VEHICLE THEFT SECURITY SYSTEM (VTSS)
The vehicle theft security system is controlled by the body control module and is standard equipment on all Prowler vehicles. It monitors the doors, decklid, hood and ignition circuit to determine if the alarm should be triggered and engine disabled. When the system is armed, the BCM removes the ground from the decklid release switch thereby preventing a thief from accessing the trunk area.

When the alarm is triggered, the engine becomes disabled. In addition the horn is pulsed, the head-lamps and marker lights will flash for (3) three minutes. After the 3 minute alarm has expired the BCM will return to an armed state and ignore the input(s) that triggered the initial alarm, unless those inputs return to an inactive state. The VTSS LED will also flash at a new rate indicating that the vehicle has been tampered with. All other monitored inputs will re-trigger the (3) minute alarm if they become active.

If during the (3) minute alarming period the BCM receives a request from the RKE module to enter panic mode, the BCM will cancel the (3) minute alarm, return to VTSS armed state and then perform the RKE panic feature.

WIPER SYSTEM
The wiper system provides the driver with normal wipe (low and high speeds), intermittent wipe, wipe after wash, and pulse wipe functions. The driver selects the wiper function via a resistive multiplexed stalk switch mounted on the steering column. The low and high speeds are directly controlled via the multifunction switch. The intermittent function is controlled through the intermittent wiper relay and the BCM.

System Features
Speed Sensitive Intermittent Wipe Mode - There are 6 individual delay times with a minimum delay of 0.5 second to a maximum of 18 seconds.

When the vehicle speed is under 10 mph, the delay time is doubled providing a range of 1 second to 36 seconds.

Pulse Wipe - When the wiper is in the OFF position and the driver presses the wash button for more than 62 milliseconds, but less than 0.5 second, 1 wipe cycle in low speed mode will be provided.

Wipe After Wash Mode - When the driver presses the wash button for over 0.5 second and then releases it, the wiper will continue to run for 2 additional wiper cycles.

The wiper system utilizes the BCM to provide intermittent operation. The low and high speed are run directly from the multifunction switch. The BCM controls the intermittent relay to change the wiper delay as the multifunction switch input changes. The BCM uses vehicle speed input to double the usual delay times below 10 mph.

USING THE DRBIII(R)
Refer to the DRBIII(R) user's guide for instructions and assistance with reading trouble codes, erasing trouble codes, and other DRBIII(R) functions.

DRBIII(R) Error Message
Under normal operation, the DRBIII(R) will display one of only two error messages:
- User-Requested WARM Boot or User-Requested COLD Boot

This is a sample of such an error message display:
ver: 2.14
date: 26 Jul93
file: key_itf.cc
date: Jul 26 1993
line: 548
err: Ox1
User-Requested COLD boot

Press more to switch between this display and the application screen.

Press F4 when done noting information

DRBIII(R) Does Not Power Up (blank Screen)
If the LED's do not light or no sound is emitted at start up, check for loose cable connections or a bad cable. Check the vehicle battery voltage (data link connector cavity 16). A minimum of 11 volts is required to adequately power the DRBIII(R). Check for proper ground connection at cavities 4 and 5.

If all connections are proper between the DRBIII(R) and the vehicle or other devices, and the vehicle battery is fully charged, an inoperative DRBIII(R) may be the result of a faulty cable or vehicle wiring.

DRB III(R) Scan Tool:

Display Is Not Visible
Low temperatures Will affect the visibility of the display. Adjust the contrast to compensate for this condition.

WARNINGS
Vehicle Damage Warnings
Before disconnecting any control module, make sure the ignition is "OFF". Failure to do so could damage the module.

When testing voltage or continuity at any control module, use the terminal side (not the wire end) of the connector. Do not probe a wire through the insulation; this will damage it and eventually cause it to fail because of corrosion.

Be careful when performing electrical tests so as to prevent accidental shorting of terminals. Such mistakes can damage fuses or components. Also, a second code could be set, making diagnosis of the original problem more difficult.

Road Testing A Complaint Vehicle
Some complaints will require a test drive as part of the repair verification procedure. The purpose of the test drive is to try to duplicate the diagnostic code or symptom condition.

CAUTION: BEFORE ROAD TESTING A VEHICLE, BE SURE THAT ALL COMPONENTS ARE REASSEMBLED. DURING THE TEST DRIVE, DO NOT TRY TO READ THE DRBIII(R) SCREEN WHILE IN MOTION. DO NOT HANG THE DRBIII(R) FROM THE REAR VIEW MIRROR OR OPERATE IT YOURSELF. HAVE AN ASSISTANT AVAILABLE TO OPERATE THE DRBIII(R).

REQUIRED TOOLS AND EQUIPMENT
Airbag System Load Tool (8310)
DRBIII(R) (diagnostic read-out box)
Jumper Wires
Ohmmeter
Voltmeter
Test Light

GLOSSARY OF ACRONYMS
ABS antilock brake system
ACM airbag control module
BUX built up export
CAB controller antilock brake
CCD Chrysler Collision Detection Multiplex System (vehicle communication bus)
DAB driver airbag
DLC data link connector
DTC diagnostic trouble code
LHD left hand drive
MIC mechanical instrument cluster
PAB passenger airbag
PCM powertrain control module
PDC power distribution center
PWM pulse width modulated
RHD right hand drive
RKE remote keyless entry
SKIM sentry key immobilizer module
SKIS sentry key immobilizer system
SQUIB also called initiator (located in rear of airbag module)
TCM transmission control module
VFD vacuum fluorescent display
VTSS vehicle theft security system
SRS Supplemental Restraint System