1993 CHEVROLET DYNASTY boot

REAR SEAT BACK INSTALLATION
Reverse the preceding operation.
SEAT BACK BOLSTER CUSHION REMOVAL (FIG. 37)
(1) Remove rear seat cushion and back as neces-
sary. (2) Remove bolts holding outboard seat back bol-
ster to quarter panel. (3) Lift bolster upward to disengage hook retainer
on back of bolster and separate from vehicle.
SEAT BACK BOLSTER CUSHION INSTALLATION
Reverse the preceding operation
FRONT CENTER CONSOLE
REMOVAL (FIG. 38)
(1) Position front seats full forward.
(2) Remove gear selector knob and PRNDL on ve-
hicles with automatic transaxle. Remove illumina-
tion lamp socket and position socket out of the way. (3) Lift gear shift boot adapter from console and
push adapter through opening in console on vehicles
with manual transaxle. (4) Remove bolts holding arm rest riser to floor
bracket. (5) Separate rear console from floor and remove
from vehicle. (6) Position front seats full rearward.
(7) Remove radio bezel from instrument panel. Re-
fer to Group 8E, Instrument Panel. Remove screws
holding console to instrument panel. (8) Remove screws holding forward console to
lower instrument panel rail. (9) Remove screws holding forward console to for-
ward brace. (10) Separate forward console from vehicle.
INSTALLATION
Reverse the preceding operation. Verify PRNDL
adjustment before returning vehicle to use.
FLOOR CARPET
REMOVAL (FIG. 39)
(1) Remove cowl trim panels and scuff plates.
(2) Remove front seats and inboard seat belts.
(3) Remove center arm rest and front console.
(4) Remove outboard seat belt lower attaching
bolts. (5) Remove rear seat cushion.
(6) Pull carpet from under B-pillar trim covers.
(7) Fold carpet and remove through front door
opening.
INSTALLATION
Reverse the preceding operation.
OVERHEAD CONSOLE
REMOVAL (FIG. 40)
(1) Remove screws holding overhead console to re-
inforcement bracket. (2) Slide overhead console rearward to separate re-
inforcement bracket retainer tab from console. (3) Lower console from roof and disconnect wire
connectors.
Fig. 37 Rear Seat Back and Bolster
Fig. 38 Front Center Console
Ä AP-BODY 23 - 113

(1) Attach manifold gauge set.
(2) Open the windows of the passenger compart-
ment and set the air conditioning controls to A/C,
RECIRC, and Low blower speed. (3) Start the engine and allow it to warm up to
normal running temperature. (4) If the air conditioning compressor does not en-
gage, disconnect the low pressure cut-off switch.
Place a jumper wire across the terminals in the con-
nector boot. If the compressor still does not engage, a
problem exists in the compressor clutch feed circuit. (6) Hold the engine speed at 1400 rpm.
(7) Following the instructions provided with the
charging equipment being used. Charge through the
suction side of the system. Use enough refrigerant to
clear the sight glass in the filter drier. (8) At the point when the sight glass clears, note
the weight of the refrigerant supply drum or the
level in the charging cylinder. Then add an addi-
tional 340 g (12 oz) of refrigerant to the system. Re- move the jumper wire from the low pressure cut-off
switch connector and connect the cut-off switch.
(9) Test the over all performance of the air condi-
tioner as described in A/C Overall Performance Test
in this Group. Close all valves on the charging equip-
ment and disconnect the hoses from the service ports
as described in the Manifold Gauge Set Connections
section of this Group. Install the service port caps.
DISCHARGING REFRIGERANT SYSTEM
(R-12) refrigerant is a chlorofluorocarbon (CFC)
that can contribute to the depletion of the ozone
layer in the upper atmosphere. To help protect the
ozone layer, an R-12 refrigerant recycling device
must be used. Use this device when it is necessary to
empty the refrigerant system. Contact an automotive
service equipment supplier for refrigerant recycling
equipment. Refer to the operating instructions pro-
vided with the recycling equipment for proper opera-
tion.
EVACUATING REFRIGERANT SYSTEM
If the A/C system has been open to the atmosphere,
it must be evacuated before the system can be
charged. Moisture and air mixed with the refrigerant
will raise the compressor head pressure above accept-
able operating levels. This will reduce the perfor-
mance of the air conditioner and damage the
compressor. Moisture will boil at near room temper-
ature when exposed to vacuum. To evacuate the re-
frigerant system: (1) Connect a suitable charging station, refrigerant
recovery machine, and a manifold gauge set with
vacuum pump. (2) Open the suction and discharge valves and
start the vacuum pump. When the suction gauge
reads -88 kPa (-26 in. Hg) vacuum or greater, close
all valves and turn off vacuum pump. If the system
fails to reach specified vacuum, the refrigerant sys-
tem likely has a leak that must be corrected. If the
refrigerant system maintains specified vacuum for at
least 30 minutes, start the vacuum pump. Then open
the suction and discharge valves, and allow the sys-
tem to evacuate an additional 10 minutes. (3) Close all valves. Turn off and disconnect the
vacuum pump. The refrigerant system is prepared to be charged
with refrigerant.
CHARGING REFRIGERANT SYSTEMÐEMPTY
SYSTEM
CAUTION: Do not over charge refrigerant system,
as excessive compressor head pressure can cause
noise and system failure.
Fig. 6 Testing for A/C LeaksÐTypical Front/Rear A/C System
Ä HEATING AND AIR CONDITIONING 24 - 11

WARNING: AVOID RADIATOR/CONDENSER FAN
BLADES WHEN WORKING IN THE RADIATOR
AREA. FAN IS CONTROLLED BY TEMPERATURE
AND CAN START ANY TIME IGNITION IS ON. PER-
SONAL INJURY CAN RESULT.
(1) Disconnect fan control switch wire connector.
(2) Using a suitable jumper wire, jump across ter-
minals in wire connector. (3) Connect a suitable continuity tester across fan
control switch terminals. (4) Start engine and set idle at 1300 rpm. The ra-
diator fan should run constantly. (5) Set the A/C controls to A/C and high blower.
(6) If the high pressure gauge reads below 1102
kPa (160 psi) there should be no continuity across
the switch terminals.
CAUTION: Do not allow engine to overheat when ra-
diator air flow is blocked.
(7) Block radiator air flow with a suitable cover to
increase the high side pressure to at least 1585 kPa
(230 psi). Electrical continuity should be detected
across the fan control switch terminals. (8) Remove cover from front of vehicle to allow
high side pressure to decrease. When pressure drops
below 1102 kPa (160 psi), continuity should cease. If fan control switch is defective, replace it.
REMOVAL AND INSTALLATION
CAUTION: Refrigerant removal is not necessary
when removing the Condenser Fan Control Switch.
However, a small amount of refrigerant will vent
from the switch port. Review the refrigerant han-
dling section of Safety Precautions and Warnings in
the General Information section of this Group.
(1) Disconnect wire connector from condenser fan
control switch. (2) Loosen and quickly rotate the switch counter-
clockwise and separate from the high pressure line
switch port. To install, reverse the preceding operation.
DIFFERENTIAL PRESSURE CUT-OUT SWITCH
DIAGNOSIS
The Differential Pressure Cut-Out (DPCO) Switch
(Fig. 3) monitors the liquid refrigerant pressure on
the liquid side of the system. The DPCO is located on
the expansion valve. The expansion valve is black in
color when a variable displacement compressor is
used. The DPCO turns off voltage to the compressor
clutch coil when liquid refrigerant pressure drops to
levels that could damage the compressor. The DPCO
is a sealed factory calibrated unit. It must be re-
placed if defective.
DPCO SWITCH DIAGNOSIS
The work area must not be below 10ÉC (50ÉF) to
test the compressor clutch circuit. (1) With gear selector in park or neutral, and park
brake set, start engine and allow to idle. (2) Raise hood and disconnect DPCO switch con-
nector boot. (3) Using a suitable jumper wire, jump across the
terminals inside wire connector boot. (4) If clutch does not engage, the wiring, fuse, re-
lay, ambient switch, or high pressure cut-off switch
can be defective. Refer to Group 8W, Wiring Dia-
grams. (5) If clutch engages, connect a suitable manifold
gauge set. Read low pressure gauge. At pressure 283
kPa (41 psi) and above, DPCO switch will complete
the clutch circuit. If the low pressure gauge reads be-
low 317 kPa (46 psi), the system is low on refrigerant
charge or empty due to a leak. Refer to Testing For
Refrigerant Leaks in the Refrigerant Service Proce-
dures section. (6) Install connector boot on switch and repeat step
number 3. If the clutch does not engage, replace the
DPCO switch.
TEMPERATURE CONTROL CABLEÐAC/AY MODELS
REMOVAL AND INSTALLATION
A Temperature Control Cable is used on non-ATC
heat or heater-A/C systems only. ATC (Automatic
Temperature Control) systems use an electrically op-
erated temperature control. Refer to the ATC section
of this Group. (1) Remove the A/C-Heater control panel assembly.
Refer to A/C-Heater Control Replacement in Group
8E Instrument Panel. Disconnect the cable attaching
flag from the A/C-heater control and remove the ca-
ble from control panel.
Fig. 3 Differential Pressure Cut-Out Switch
24 - 48 HEATING AND AIR CONDITIONING Ä

housing) through the hole in the housing. Feed the
wire harness and connector through the opening and
into the housing (Fig. 19). (3) Work through the air inlet opening (to the left of
the blower motor wheel). Pull the fin-sensing cycling
switch from the A/C evaporator (Fig. 20). The metal
probe on the switch is pushed into the evapora-
tor approximately three inches.
To install, reverse the preceding operation. The
switch probe should not be installed in the original
location (hole). Insert the probe in the evaporator coil
approximately 5 mm (3 to 4 fins) to the right or left of
the position it was removed. This will insure correct
temperature sensing and system performance. Exces-
sive force should not be required for probe insertion.
Care should be taken not to damage the A/C evaporator
coil or the switch probe.
LOW OR DIFFERENTIAL PRESSURE CUT-OFF
SWITCH
The Low Pressure Cut-Off (LPCO) Switch (Fig. 21)
monitors the refrigerant gas pressure on the suction side of the system. The LPCO is located on the ex-
pansion valve, and the expansion valve is silver in
color when a fixed displacement compressor is used.
The LPCO turns off voltage to the compressor clutch
coil when refrigerant gas pressure drops to levels
that could damage the compressor. The LPCO is a
sealed factory calibrated unit. It must be replaced if
defective.
LPCO SWITCH DIAGNOSIS
The work area must not be below 10ÉC (50ÉF) to
test the compressor clutch circuit. (1) With gear selector in park or neutral and park
brake set, start engine and allow to idle. (2) Raise hood and disconnect LPCO switch con-
nector boot. (3) Using a suitable jumper wire, jump across the
terminals inside wire connector boot. (4) If the compressor clutch does not engage, the
cycling clutch switch, wiring, relay, or fuse can be
defective. Refer to Group 8W, Wiring Diagrams. (5) If clutch engages, connect manifold gauge set.
Read low pressure gauge. At pressure above 97 kPa
(14 psi) and above, LPCO switch will complete the
clutch circuit. If the low pressure gauge reads below
172 kPa (25 psi), the system is low on refrigerant
charge or empty due to a leak. Refer to Testing For
Refrigerant Leaks in the Refrigerant Service Proce-
dures section. (6) Install connector boot on switch and repeat step
number 3. If the clutch does not engage, replace the
LPCO switch.
REMOVAL AND INSTALLATION
WARNING: THE REFRIGERATION SYSTEM MUST
BE COMPLETELY EMPTY BEFORE PROCEEDING
WITH THIS OPERATION. REFER TO REFRIGERANT
RECOVERY SECTION.
Fig. 21 Low Pressure Cut-Off Switch
Fig. 19 Remove or Install Wire Harness Grommet
Fig. 20 Remove or Install Fin-sensing Cycling Clutch Switch
24 - 54 HEATING AND AIR CONDITIONING Ä

(1) Disconnect the boot like wire connector at the
cut-off switch. (2) Using a sender unit type socket, remove the
switch from the expansion valve (Fig. 22 or 23).
To install, assure an adequate seal by using a small
amount of thread sealing tape on the replacement
switch and reverse the preceding steps. Evacuate and charge the system.
EXPANSION VALVE
DIAGNOSIS
BLACK EXPANSION VALVE TEST
Liquid CO
2is required to test the expansion
valve. It is available from most welding supply
facilities. CO
2is also available from companies
which service and sell fire extinguishers. Review Safety Precautions and Warnings before pro-
ceeding with this operation. The work area must be 21ÉC to 27ÉC (70ÉF to 85ÉF) when testing expansion
valve. To test the expansion valve: (1) Connect a charging station or manifold gauge set
to the refrigerant system service ports. (2) Verify the refrigerant charge level using the sight
glass method. (3) Disconnect the wire connector at the differential
pressure cut-off switch. Using a jumper wire, jump
across the terminals inside the connector boot (Fig. 24).
(4) Close all doors, windows and vents to the passen-
ger compartment. (5) Set heater-A/C control to A/C, full heat, FLOOR,
and high blower. (6) Start the engine and hold the idle speed (1000
rpm). After the engine has reached running tempera-
ture, allow the passenger compartment to heat up.
This will create the need for maximum refrigerant flow
into the evaporator. (7) Discharge (high pressure) gauge should read 965
to 1655 kPa (140 to 240 psi) when the refrigerant
charge is sufficient. If system cannot achieve proper
pressure, replace the expansion valve. If pressure is
correct, record reading and proceed with test.
WARNING: PROTECT SKIN AND EYES FROM CON-
TACTING CO
2PERSONAL INJURY CAN RESULT.
(8) If discharge pressure is within specified range,
freeze the expansion valve control head (Fig. 8) for
30 seconds. Use a super cold substance (liquid
CO
2). Do not spray R-12 Refrigerant on the expan-
sion valve for this test. Refer to Refrigerant
Recycling in the Refrigerant Service Procedures
section. If compressor discharge (high) pressure does
not drop by 15% or more than the pressure recorded in
step 7, replace the expansion valve. Allow the expan-
sion valve to thaw. The discharge pressure should
Fig. 22 Low Pressure Cut-Off Switch and Expansion ValveÐTypical
Fig. 23 Differential Pressure Cut-Off Switch and Ex-pansion ValveÐTypical
Fig. 24 Differential Pressure Cut-Out Switch
Ä HEATING AND AIR CONDITIONING 24 - 55

stabilize to the pressure recorded in step 7. If the
pressure does not stabilize, replace the expansion
valve.When expansion valve tests are complete, refer to
Heater and A/C Performance Tests and remove all test
equipment before returning vehicle to use.
SILVER EXPANSION VALVE TEST
Expansion valve tests should be performed af-
ter compressor tests. Liquid CO
2is required to test the expansion
valve. It is available from most welding supply
facilities. CO
2is also available from companies
which service and sell fire extinguishers. Review Safety Precautions and Warnings in the
General Information section of this Group. The work
area and vehicle must be 21ÉC to 27ÉC (70ÉF to 85ÉF)
when testing expansion valve. To test the expansion
valve: (1) Connect a charging station or manifold gauge set
to the refrigerant system service ports. (2) Verify the refrigerant charge level using the sight
glass method. (3) Disconnect wire connector at low pressure cut-off
switch (Fig. 25). Using a jumper wire, jump terminals
inside wire connector boot.
(4) Close all doors, windows and vents to the passen-
ger compartment. (5) Set heater-A/C control to A/C, full heat, FLOOR,
and high blower. (6) Start the engine and hold the idle speed (1000
rpm). After the engine has reached running tempera-
ture, allow the passenger compartment to heat up.
This will create the need for maximum refrigerant flow
into the evaporator. (7) If the refrigerant charge is sufficient, discharge
(high pressure) gauge should read 965 to 1655 kPa (140
to 240 psi). Suction (low pressure) gauge should read
140 kPa to 207 kpa (20 psi to 30 psi). If system cannot achieve proper pressure readings, replace the
expansion valve. If pressure is correct, proceed with
test.
WARNING: PROTECT SKIN AND EYES FROM CON-
TACTING CO
2PERSONAL INJURY CAN RESULT.
(8) If suction side low pressure is within specified
range, freeze the expansion valve control head (Fig. 26)
for 30 seconds. Use a super cold substance (liquid CO
2).
Do not spray R-12 Refrigerant on the expansion
valve for this test. Suction side low pressure should
drop to -50 kPa (-15 in. Hg) If not, replace expansion
valve.
(9) Allow expansion valve to thaw. The low pressure
gauge reading should stabilize at 140 kPa to 240 kPa
(20 psi to 30 psi). If not, replace expansion valve. When expansion valve test is complete, test A/C
overall performance. Refer to the Heater and A/C
Performance Test in this section. Remove all test
equipment before returning vehicle to use.
REMOVAL
WARNING: THE REFRIGERATION SYSTEM MUST BE
COMPLETELY EMPTY BEFORE PROCEEDING WITH
THIS OPERATION.
(1) Remove the boot-type wire connector from the
pressure cut-off switch. (2) Remove the attaching bolt in center of refriger-
ant line-plumbing sealing plate (Fig. 27). (3) Carefully pull the refrigerant line-sealing plate
assembly from the expansion valve towards front of
vehicle. Do Not scratch the expansion valve sealing
surfaces with pilot tubes. (4) Cover the openings on A/C line-sealing plate
assembly to prevent contamination. (5) Remove two screws securing the expansion valve
to the evaporator sealing plate. (6) Carefully remove valve.
Fig. 25 Low Pressure Cut-Off Switch
Fig. 26 Expansion Valve
24 - 56 HEATING AND AIR CONDITIONING Ä

During the cold start warm-up period and the hot
start time delay, the PCM does not energize the so-
lenoid. When de-energized, no vapors are purged.
The PCM de-energizes the solenoid during open loop
operation. The engine enters closed loop operation after it
reaches a specified temperature and the time delay
ends. During closed loop operation, the PCM ener-
gizes and de-energizes the solenoid approximately 5
to 10 times per second, depending upon operating
conditions. The PCM varies the vapor flow rate by
changing solenoid pulse width. Pulse width is the
amount of time the solenoid energizes. The PCM ad-
justs solenoid pulse width based on engine air flow. A rubber boot covers the duty cycle EVAP purge
solenoid. On 2.5L MPI flexible fuel AA-body vehicles,
the solenoid and bracket attach to the EVAP canister
mounting studs (Fig. 7). On vehicles with 3.0L en-
gines, the solenoid attaches to a bracket mounted to
the right engine mount (Fig. 8). The top of the sole-
noid has the word TOP on it. The solenoid will not
operate unless it is installed correctly.
PRESSURE-VACUUM FILLER CAP
CAUTION: Remove the fuel filler cap to relieve fuel
tank pressure. Remove the cap before disconnect-
ing fuel system components or servicing the fuel
tank.
A pressure-vacuum relief cap seals the fuel tank
(Fig. 9). Tightening the cap on the fuel filler tube
forms a seal between them. The relief valves in the
cap are a safety feature. They prevent possible exces-
sive pressure or vacuum in the tank. Excessive fuel
tank pressure could be caused by a malfunction in
the system or damage to the vent lines. The seal between the cap and filler tube breaks
when the cap is removed. Removing the cap breaks
the seal and relieves fuel tank pressure. If the filler cap needs replacement, only use a sim-
ilar unit.
Fig. 6 Canister Purge SolenoidÐExcept 3.0L and 2.5L MPI
Fig. 7 Duty Cycle EVAP Purge SolenoidÐ2.5L MPIFlexible Fuel AA-Body
Fig. 8 Duty Cycle EVAP Purge SolenoidÐ3.0L Engine
Fig. 9 Pressure Vacuum Filler Cap
25 - 14 EMISSION CONTROL SYSTEMS Ä