2002 JEEP LIBERTY length

(3) There should be continuity. The ohmmeter
should register only a fraction of an ohm resistance.
High or infinite resistance indicates a damaged or
open antenna conductor. If OK, go to Test 3. If not
OK, isolate and test each of the individual antenna
conductor components. Replace only the faulty
antenna conductor component.
TEST 3
Test 3 checks the condition of the vehicle body
ground connection. To begin this test, proceed as fol-
lows:
(1) This test must be performed with the battery
positive cable disconnected from the battery. Discon-
nect and isolate both battery cables, negative cable
first.
(2) Reconnect the battery negative cable.
(3) Touch one ohmmeter test lead to a good clean
ground point on the vehicle fender. Touch the other
test lead to the battery negative terminal post. Check
the ohmmeter reading for continuity.
(4) There should be continuity. The ohmmeter
should register less than one ohm resistance. High or
infinite resistance indicates a loose, corroded, or
damaged connection between the battery negative
terminal and the vehicle body. If OK, go to Test 4. If
not OK, check the battery negative cable connection
to the vehicle body and the radio noise suppression
ground strap connections to the engine and the vehi-
cle body for being loose or corroded. Clean or tighten
these connections as required.
TEST 4
Test 4 checks the condition of the connection
between the antenna coaxial cable shield and the
vehicle body ground as follows:
(1) Disconnect and isolate the antenna coaxial
cable connector behind the right side kick panel.
(2) Touch one ohmmeter test lead to a good clean
ground point on the vehicle fender. Touch the other
test lead to the outer crimp on the antenna coaxial
cable connector. Check the ohmmeter reading for con-
tinuity.
(3) There should be continuity. The ohmmeter
should register less than one ohm resistance. High or
infinite resistance indicates a loose, corroded, or
damaged connection between the antenna body and
the vehicle body or between the antenna body and
the antenna coaxial cable shield. If not OK, clean the
antenna body to fender mating surfaces and tighten
the antenna cap nut to specifications.
(4) Check the resistance again with an ohmmeter.
If the resistance is still more then one ohm, replace
the faulty antenna body and cable.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the antenna mast.
(3) Remove cover (Fig. 3).
(4) Remove mounting nut.
(5) Remove bezel adapter.
(6) Remove right kick panel trim.
(7) Disconnect antenna body and cable from the
instrument panel cable. Attach a wire or string
(approximately 2 feet in length) to the cable to aid in
installation of the new cable.
(8) Remove the upper fender mounting bolts.
Loosen the two fender mounting bolts located near
the upper door hinge (Refer to 23 - BODY/EXTERI-
OR/FRONT FENDER - REMOVAL).
(9) Carefully pull fender out to access the antenna
body and cable. Pull cable up through the opening
with wire attached.
INSTALLATION
(1) Attached wire to new cable. Pull fender out and
insert cable into opening.
(2) Pull cable through hole in kick panel area
using the attached wire.
(3) Connect antenna body cable to the instrument
panel cable.
(4) Install right kick panel trim.
(5) Install bezel adapter.
(6) Install mounting nut. Tighten to 12 N´m (105
in. lbs.).
(7) Install cover.
Fig. 3 ANTENNA BODY AND CABLE
1 - ANTENNA MAST
2 - ANTENNA COVER
3 - ANTENNA BASE MOUNTING NUT
4 - ANTENNA BEZEL ADAPTER
5 - ANTENNA BODY AND CABLE
8A - 6 AUDIOKJ
ANTENNA BODY & CABLE (Continued)

ness routing and retention, connector pin-out infor-
mation and location views for the various wire
harness connectors, splices and grounds.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel center trim
panel.
(3) Remove the radio mounting screws (Fig. 7).
(4) Disconnect the antenna cable by pulling the
locking antenna connector away from the radio (Fig.
8).
(5) Disconnect the electrical harness connector(s).
(6) Remove radio from instrument panel.
INSTALLATION
(1) Connect the wire harness connector(s).
(2) Connect the antenna cable.
(3) Install the radio to the instrument panel.
(4) Install the radio mounting screws.
(5) Install the instrument panel center trim panel.
(6) Connect the battery negative cable.
RADIO NOISE SUPPRESSION
GROUND STRAP
DESCRIPTION
Radio noise suppression devices are factory-in-
stalled standard equipment on this vehicle. Radio
Frequency Interference (RFI) and ElectroMagnetic
Interference (EMI) can be produced by any on-board
or external source of electromagnetic energy. These
electromagnetic energy sources can radiate electro-
magnetic signals through the air, or conduct them
through the vehicle electrical system.
When the audio system converts RFI or EMI to an
audible acoustic wave form, it is referred to as radio
noise. This undesirable radio noise is generally man-
ifested in the form of ªbuzzing,º ªhissing,º ªpopping,º
ªclicking,º ªcrackling,º and/or ªwhirringº sounds. In
most cases, RFI and EMI radio noise can be sup-
pressed using a combination of vehicle and compo-
nent grounding, filtering and shielding techniques.
This vehicle is equipped with factory-installed radio
noise suppression devices that were designed to min-
imize exposure to typical sources of RFI and EMI;
thereby, minimizing radio noise complaints.
Factory-installed radio noise suppression is accom-
plished primarily through circuitry or devices that
are integral to the factory-installed radios, audio
power amplifiers and other on-board electrical com-
ponents such as generators, wiper motors, blower
motors, and fuel pumps that have been found to be
potential sources of RFI or EMI. External radio noise
suppression devices that are used on this vehicle to
control RFI or EMI, and can be serviced, include the
following:
²Engine-to-body ground strap- This length of
braided ground strap has an eyelet terminal connec-
tor crimped to each end. One end is secured to the
engine cylinder head(s). The other is secured to the
plenum.
²Resistor-type spark plugs- This type of spark
plug has an internal resistor connected in series
between the spark plug terminal and the center elec-
trode to help reduce the production of electromag-
netic radiation that can result in radio noise.
Fig. 7 RADIO
Fig. 8 ANTENNA TO RADIO
1 - RADIO
2 - LOCKING ANTENNA CONNECTOR
3 - INSTRUMENT PANEL ANTENNA CABLE
KJAUDIO 8A - 9
RADIO (Continued)

ison, the prior two-wire Chrysler Collision Detection
(CCD) data bus system is designed to run at 7.8125
Kbps.
The voltage network used to transmit messages
requires biasing and termination. Each module on
the PCI data bus system provides its own biasing
and termination. Each module (also referred to as a
node) terminates the bus through a terminating
resistor and a terminating capacitor. There are two
types of nodes on the bus. The dominant node termi-
nates the bus througha1KWresistor and a 3300 pF
capacitor. The Powertrain Control Module (PCM) is
the only dominant node for the PCI data bus system.
A standard node terminates the bus through an 11
KW resistor and a 330 pF capacitor.
The modules bias the bus when transmitting a
message. The PCI bus uses low and high voltage lev-
els to generate signals. Low voltage is around zero
volts and the high voltage is about seven and one-
half volts. The low and high voltage levels are gener-
ated by means of variable-pulse width modulation to
form signals of varying length. The Variable Pulse
Width Modulation (VPWM) used in PCI bus messag-
ing is a method in which both the state of the bus
and the width of the pulse are used to encode bit
information. A9zero9bit is defined as a short low
pulse or a long high pulse. A9one9bit is defined as a
long low pulse or a short high pulse. A low (passive)
state on the bus does not necessarily mean a zero bit.
It also depends upon pulse width. If the width is
short, it stands for a zero bit. If the width is long, it
stands for a one bit. Similarly, a high (active) state
does not necessarily mean a one bit. This too depends
upon pulse width. If the width is short, it stands for
a one bit. If the width is long, it stands for a zero bit.
In the case where there are successive zero or one
data bits, both the state of the bus and the width of
the pulse are changed alternately. This encoding
scheme is used for two reasons. First, this ensures
that only one symbol per transition and one transi-
tion per symbol exists. On each transition, every
transmitting module must decode the symbol on the
bus and begin timing of the next symbol. Since tim-
ing of the next symbol begins with the last transition
detected on the bus, all of the modules are re-syn-
chronized with each symbol. This ensures that thereare no accumulated timing errors during PCI data
bus communication.
The second reason for this encoding scheme is to
guarantee that the zero bit is the dominant bit on
the bus. When two modules are transmitting simul-
taneously on the bus, there must be some form of
arbitration to determine which module will gain con-
trol. A data collision occurs when two modules are
transmitting different messages at the same time.
When a module is transmitting on the bus, it is read-
ing the bus at the same time to ensure message
integrity. When a collision is detected, the module
that transmitted the one bit stops sending messages
over the bus until the bus becomes idle.
Each module is capable of transmitting and receiv-
ing data simultaneously. The typical PCI bus mes-
sage has the following four components:
²Message Header- One to three bytes in length.
The header contains information identifying the mes-
sage type and length, message priority, target mod-
ule(s) and sending module.
²Data Byte(s)- This is the actual message that
is being sent.
²Cyclic Redundancy Check (CRC) Byte- This
byte is used to detect errors during a message trans-
mission.
²In-Frame Response (IFR) byte(s)-Ifa
response is required from the target module(s), it can
be sent during this frame. This function is described
in greater detail in the following paragraph.
The IFR consists of one or more bytes, which are
transmitted during a message. If the sending module
requires information to be received immediately, the
target module(s) can send data over the bus during
the original message. This allows the sending module
to receive time-critical information without having to
wait for the target module to access the bus. After
the IFR is received, the sending module broadcasts
an End of Frame (EOF) message and releases control
of the bus.
The PCI data bus can be monitored using the
DRBIIItscan tool. It is possible, however, for the bus
to pass all DRBIIIttests and still be faulty if the
voltage parameters are all within the specified range
and false messages are being sent.
KJELECTRONIC CONTROL MODULES 8E - 9
COMMUNICATION (Continued)

²Output Shaft Speed Sensor
²Line Pressure Sensor
Some examples ofindirect inputsto the TCM are:
²Engine/Body Identification
²Manifold Pressure
²Target Idle
²Torque Reduction Confirmation
²Engine Coolant Temperature
²Ambient/Battery Temperature
²DRBtScan Tool Communication
Based on the information received from these var-
ious inputs, the TCM determines the appropriate
shift schedule and shift points, depending on the
present operating conditions and driver demand.
This is possible through the control of various direct
and indirect outputs.
Some examples of TCMdirect outputsare:
²Transmission Control Relay
²Solenoids
²Torque Reduction Request
Some examples of TCMindirect outputsare:
²Transmission Temperature (to PCM)
²PRNDL Position (to BCM)
In addition to monitoring inputs and controlling
outputs, the TCM has other important responsibili-
ties and functions:
²Storing and maintaining Clutch Volume Indexes
(CVI)
²Storing and selecting appropriate Shift Sched-
ules
²System self-diagnostics
²Diagnostic capabilities (with DRBtscan tool)
NOTE: If the TCM has been replaced, the ªQuick
Learn Procedureº must be performed. (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MODULES/
TRANSMISSION CONTROL MODULE - STANDARD
PROCEDURE)
BATTERY FEED
A fused, direct battery feed to the TCM is used for
continuous power. This battery voltage is necessary
to retain adaptive learn values in the TCM's RAM
(Random Access Memory). When the battery (B+) is
disconnected, this memory is lost. When the battery
(B+) is restored, this memory loss is detected by the
TCM and a Diagnostic Trouble Code (DTC) is set.
CLUTCH VOLUME INDEXES (CVI)
An important function of the TCM is to monitor
Clutch Volume Indexes (CVI). CVIs represent the vol-
ume of fluid needed to compress a clutch pack.
The TCM monitors gear ratio changes by monitor-
ing the Input and Output Speed Sensors. The Input,
or Turbine Speed Sensor sends an electrical signal to
the TCM that represents input shaft rpm. The Out-put Speed Sensor provides the TCM with output
shaft speed information.
By comparing the two inputs, the TCM can deter-
mine transmission gear position. This is important to
the CVI calculation because the TCM determines
CVIs by monitoring how long it takes for a gear
change to occur (Fig. 13).
Gear ratios can be determined by using the DRBt
Scan Tool and reading the Input/Output Speed Sen-
sor values in the ªMonitorsº display. Gear ratio can
be obtained by dividing the Input Speed Sensor value
by the Output Speed Sensor value.
For example, if the input shaft is rotating at 1000
rpm and the output shaft is rotating at 500 rpm,
then the TCM can determine that the gear ratio is
2:1. In direct drive (3rd gear), the gear ratio changes
to 1:1. The gear ratio changes as clutches are applied
and released. By monitoring the length of time it
takes for the gear ratio to change following a shift
request, the TCM can determine the volume of fluid
used to apply or release a friction element.
The volume of transmission fluid needed to apply
the friction elements are continuously updated for
adaptive controls. As friction material wears, the vol-
ume of fluid need to apply the element increases.
Fig. 13 Example of CVI Calculation
1 - OUTPUT SPEED SENSOR
2 - OUTPUT SHAFT
3 - CLUTCH PACK
4 - SEPARATOR PLATE
5 - FRICTION DISCS
6 - INPUT SHAFT
7 - INPUT SPEED SENSOR
8 - PISTON AND SEAL
KJELECTRONIC CONTROL MODULES 8E - 19
TRANSMISSION CONTROL MODULE (Continued)

subjected to a high torque load, deposits partially liq-
uefy and bridge the gap between electrodes (Fig. 23).
This short circuits the electrodes. Spark plugs with
electrode gap bridging can be cleaned using standard
procedures.
SCAVENGER DEPOSITS
Fuel scavenger deposits may be either white or yel-
low (Fig. 24). They may appear to be harmful, but
this is a normal condition caused by chemical addi-
tives in certain fuels. These additives are designed to
change the chemical nature of deposits and decrease
spark plug misfire tendencies. Notice that accumula-
tion on the ground electrode and shell area may be
heavy, but the deposits are easily removed. Spark
plugs with scavenger deposits can be considered nor-
mal in condition and can be cleaned using standard
procedures.
CHIPPED ELECTRODE INSULATOR
A chipped electrode insulator usually results from
bending the center electrode while adjusting the
spark plug electrode gap. Under certain conditions,
severe detonation can also separate the insulator
from the center electrode (Fig. 25). Spark plugs with
this condition must be replaced.
PREIGNITION DAMAGE
Preignition damage is usually caused by excessive
combustion chamber temperature. The center elec-
trode dissolves first and the ground electrode dis-
solves somewhat latter (Fig. 26). Insulators appear
relatively deposit free. Determine if the spark plug
has the correct heat range rating for the engine.
Determine if ignition timing is over advanced or if
other operating conditions are causing engine over-heating. (The heat range rating refers to the operat-
ing temperature of a particular type spark plug.
Spark plugs are designed to operate within specific
temperature ranges. This depends upon the thick-
ness and length of the center electrodes porcelain
insulator.)
SPARK PLUG OVERHEATING
Overheating is indicated by a white or gray center
electrode insulator that also appears blistered (Fig.
27). The increase in electrode gap will be consider-
ably in excess of 0.001 inch per 2000 miles of opera-
tion. This suggests that a plug with a cooler heat
range rating should be used. Over advanced ignition
timing, detonation and cooling system malfunctions
can also cause spark plug overheating.
Fig. 23 Electrode Gap Bridging
1 - GROUND ELECTRODE
2 - DEPOSITS
3 - CENTER ELECTRODE
Fig. 24 Scavenger Deposits
1 - GROUND ELECTRODE COVERED WITH WHITE OR
YELLOW DEPOSITS
2 - CENTER ELECTRODE
Fig. 25 Chipped Electrode Insulator
1 - GROUND ELECTRODE
2 - CENTER ELECTRODE
3 - CHIPPED INSULATOR
8I - 14 IGNITION CONTROLKJ
SPARK PLUG (Continued)

BRAKE LAMP SWITCH
DESCRIPTION
The brake lamp switch is a three circuit, spring-
loaded plunger actuated switch that is secured to the
steering column support bracket under the driver
side of the instrument panel (Fig. 3). The brake lamp
switch is contained within a rectangular molded plas-
tic housing with an integral connector receptacle fea-
turing six terminal pins and a red plastic Connector
Position Assurance (CPA) lock. The switch is con-
nected to the vehicle electrical system through a ded-
icated take out and connector of the instrument
panel wire harness. The switch plunger extends
through a mounting collar on one end of the switch
housing. The plunger has a one time telescoping self-
adjustment feature that is achieved after the switch
is installed by moving an adjustment release lever on
the opposite end of the switch housing clockwise,
until it locks in a position that is parallel to the con-
nector receptacle. The brake lamp switch self-adjust-
ment is a one time feature. Once the feature has
been used, the switch cannot be readjusted. A ªDO
NOT RE-INSTALLº warning is molded into the
switch housing below the connector receptacle.
An installed brake lamp switch cannot be read-
justed or repaired. If the switch is damaged, faulty,
or removed from its mounting position for any rea-
son, it must be replaced with a new unit.
OPERATION
The brake lamp switch controls three different cir-
cuits, one normally open and two normally closed.
These circuits are described as follows:
²Brake Lamp Switch Circuit- A normally
open brake lamp switch circuit receives battery cur-
rent on a fused B(+) circuit from a fuse in the Junc-
tion Block (JB), and supplies battery current to the
brake lamps and the Controller Antilock Brake
(CAB) on a brake lamp switch output circuit when
the brake pedal is depressed (brake lamp switch
plunger released).
²Brake Lamp Switch Signal Circuit- A nor-
mally closed brake lamp switch signal circuit receives
a path to ground through a splice block located in the
instrument panel wire harness with an eyelet termi-
nal connector that is secured by a nut to a ground
stud on the driver side instrument panel end bracket
near the Junction Block (JB). This circuit supplies a
ground input to the Powertrain Control Module
(PCM) on a brake lamp switch sense circuit when the
brake pedal is released (brake lamp switch plunger is
depressed).
²Speed Control Circuit- A normally closed
speed control circuit receives battery current from
the Powertrain Control Module on a speed control
supply circuit, and supplies battery current to the
speed control servo solenoids (dump, vacuum, and
vent) on a speed control brake switch output circuit
when the speed control system is turned on and the
brake pedal is released (brake lamp switch plunger is
depressed).
Concealed within the brake lamp switch housing
the components of the self-adjusting brake switch
plunger consist of a two-piece telescoping plunger, a
split plunger locking collar, and a release wedge. The
release lever has an integral shaft with a wedge that
spreads the plunger locking collar to an open or
released position. After the switch is installed and
the brake pedal is released, the plunger telescopes to
the correct adjustment position. When the release
lever is moved to the release position, the wedge is
disengaged from the locking collar causing the collar
to apply a clamping pressure to the two plunger
halves fixing the plunger length.
The brake lamp switch can be diagnosed using con-
ventional diagnostic tools and methods.
Fig. 3 Brake Lamp Switch
1 - CONNECTOR RECEPTACLE
2 - BRAKE LAMP SWITCH
3 - PLUNGER
4 - COLLAR
5 - LEVER
8L - 16 LAMPS/LIGHTING - EXTERIORKJ

(5) Discard the removed brake lamp switch.
CAUTION: Always replace a removed brake lamp
switch with a new unit. This is a one time compo-
nent and is not intended for reinstallation.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
FRONT IMPACT SENSORS, SIDE CURTAIN AIRBAG,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE, THEN
WAIT TWO MINUTES FOR THE SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE PERFORMING FUR-
THER DIAGNOSIS OR SERVICE. THIS IS THE ONLY
SURE WAY TO DISABLE THE SUPPLEMENTAL
RESTRAINT SYSTEM. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
CAUTION: Always replace a removed brake lamp
switch with a new unit. This is a one time compo-
nent and is not intended for reinstallation.
(1) While holding the brake pedal depressed, align
the tabs on the brake lamp switch locking collar with
the keyed mounting hole in the steering column sup-
port bracket (Fig. 5).
(2) Still holding the brake pedal depressed, insert
the tabs on the brake lamp switch housing through
the keyed mounting hole in the steering column sup-
port bracket until the switch is firmly seated against
the bracket.
(3) Still holding the brake pedal depressed, rotate
the switch clockwise about 30 degrees to lock the
tabs on the brake lamp switch locking collar to the
keyed mounting hole in the steering column support
bracket.
(4) Release the brake pedal.
CAUTION: Do not pull up on the brake pedal before
the switch plunger adjustment has been completed.
(5) Rotate the plunger adjustment release lever
clockwise until it locks into place parallel to the
brake lamp switch connector receptacle. This action
will set the switch plunger length to a final adjust-
ment position and cannot be undone. If not per-
formed properly the first time, a new brake lamp
switchmustbe installed.(6) Reconnect the instrument panel wire harness
connector for the brake lamp switch to the switch
connector receptacle.
(7) Reconnect the battery negative cable.
CENTER HIGH MOUNTED
STOP LAMP BULB
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the Center High Mounted Stop Lamp
(CHMSL) unit from the roof panel. (Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
CENTER HIGH MOUNTED STOP LAMP UNIT -
REMOVAL).
(3) Firmly grasp the socket on the back of the
CHMSL unit housing.
(4) Rotate the socket on the back of the CHMSL
unit housing counterclockwise about 30 degrees (Fig.
6).
(5) Pull the socket and bulb straight out of the
back of CHMSL unit housing.
(6) Pull the bulb straight out of the CHMSL unit
socket.
Fig. 6 Center High Mounted Stop Lamp Bulb
Remove/Install
1 - CHMSL UNIT
2 - BULB
3 - SOCKET
4 - BODY WIRE HARNESS CONNECTOR
8L - 18 LAMPS/LIGHTING - EXTERIORKJ
BRAKE LAMP SWITCH (Continued)

BRAKE LAMP SWITCH
DESCRIPTION
The brake lamp switch is a three circuit, spring-
loaded plunger actuated switch that is secured to the
steering column support bracket under the driver
side of the instrument panel (Fig. 3). The brake lamp
switch is contained within a rectangular molded plas-
tic housing with an integral connector receptacle fea-
turing six terminal pins and a red plastic Connector
Position Assurance (CPA) lock. The switch is con-
nected to the vehicle electrical system through a ded-
icated take out and connector of the instrument
panel wire harness. The switch plunger extends
through a mounting collar on one end of the switch
housing. The plunger has a one time telescoping self-
adjustment feature that is achieved after the switch
is installed by moving an adjustment release lever on
the opposite end of the switch housing clockwise,
until it locks in a position that is parallel to the con-
nector receptacle. The brake lamp switch self-adjust-
ment is a one time feature. Once the feature has
been used, the switch cannot be readjusted. A ªDO
NOT RE-INSTALLº warning is molded into the
switch housing below the connector receptacle.
An installed brake lamp switch cannot be read-
justed or repaired. If the switch is damaged, faulty,
or removed from its mounting position for any rea-
son, it must be replaced with a new unit.
OPERATION
The brake lamp switch controls three different cir-
cuits, one normally open and two normally closed.
These circuits are described as follows:
²Brake Lamp Switch Circuit- A normally
open brake lamp switch circuit receives battery cur-
rent on a fused B(+) circuit from a fuse in the Junc-
tion Block (JB), and supplies battery current to the
brake lamps and the Controller Antilock Brake
(CAB) on a brake lamp switch output circuit when
the brake pedal is depressed (brake lamp switch
plunger released).
²Brake Lamp Switch Signal Circuit- A nor-
mally closed brake lamp switch signal circuit receives
a path to ground through a splice block located in the
instrument panel wire harness with an eyelet termi-
nal connector that is secured by a nut to a ground
stud on the driver side instrument panel end bracket
near the Junction Block (JB). This circuit supplies a
ground input to the Powertrain Control Module
(PCM) on a brake lamp switch sense circuit when the
brake pedal is released (brake lamp switch plunger is
depressed).
²Speed Control Circuit- A normally closed
speed control circuit receives battery current from
the Powertrain Control Module on a speed control
supply circuit, and supplies battery current to the
speed control servo solenoids (dump, vacuum, and
vent) on a speed control brake switch output circuit
when the speed control system is turned on and the
brake pedal is released (brake lamp switch plunger is
depressed).
Concealed within the brake lamp switch housing
the components of the self-adjusting brake switch
plunger consist of a two-piece telescoping plunger, a
split plunger locking collar, and a release wedge. The
release lever has an integral shaft with a wedge that
spreads the plunger locking collar to an open or
released position. After the switch is installed and
the brake pedal is released, the plunger telescopes to
the correct adjustment position. When the release
lever is moved to the release position, the wedge is
disengaged from the locking collar causing the collar
to apply a clamping pressure to the two plunger
halves fixing the plunger length.
The brake lamp switch can be diagnosed using con-
ventional diagnostic tools and methods.
Fig. 3 Brake Lamp Switch
1 - CONNECTOR RECEPTACLE
2 - BRAKE LAMP SWITCH
3 - PLUNGER
4 - COLLAR
5 - LEVER
8Ls - 16 LAMPSKJ