(11) Reconnect the engine wire harness connector
for the compressor clutch coil to the coil wire harness
connector on the top of the compressor.
(12) Reinstall the serpentine accessory drive belt
(Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE
BELTS - INSTALLATION).
(13) Reconnect the battery negative cable.
(14) If a new clutch plate and/or clutch pulley are
being installed, the new clutch components must be
burnished (Refer to 24 - HEATING & AIR CONDI-
TIONING/CONTROLS/A/C COMPRESSOR CLUTCH
- STANDARD PROCEDURE).
A/C COMPRESSOR CLUTCH
COIL
DIAGNOSIS AND TESTING - COMPRESSOR
CLUTCH COIL
The air conditioning compressor clutch coil electri-
cal circuit is controlled by the ATC control module
which is integral to the heater-A/C control. Begin
testing of a suspected compressor clutch coil problem
by performing the ATC Function Test using the
DRBIIItscan tool.
A/C HEATER CONTROL
DESCRIPTION
This ATC system uses a combination of electrical
and mechanical controls. These controls provide the
vehicle operator with a number of setting options to
help control the climate and comfort within the vehi-
cle.
The A/C-heater control panel is located on the
instrument panel inboard of the steering column and
below the radio (Fig. 7). The A/C-heater control panel
contains a rotary-type temperature control knob, a
rotary-type mode control knob, a thumbwheel-type
blower motor speed control and an air conditioning
compressor push button switch and indicator lamp.
The A/C-heater control panel also features a push
button switch and indicator lamp for the residual
engine heat utilization (REST) function, cabin heater
or the heater booster (as equipped).
The A/C-heater control panel cannot be adjusted or
repaired and, if faulty or damaged, it must be
replaced.
OPERATION
To control the interior temperature, the A/C-heater
control module uses the actual values from the tem-
perature sensors and the CAN bus and compares
them with the nominal value of the temperature con-
trol switch.The A/C-heater control panel is serviced only as
complete unit and cannot be repaired. If faulty or
damaged, the entire control panel unit must be
replaced.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the center bezel from the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - REMOV-
AL).
(3) Remove the two screws that secure the A/C-
heater control to the instrument panel (Fig. 8).
(4) Pull the A/C-heater control away from the
instrument panel far enough to access the connec-
tions on the back of the control.
(5) Mark and disconnect the two control cables
from the A/C-heater control.
Fig. 7 A/C-Heater Control Panel
24 - 12 CONTROLS - FRONTVA
A/C COMPRESSOR CLUTCH (Continued)
