1988 PONTIAC FIERO air conditioning

"18-16 AIR CONDITIONING
B . Accumulator dehydrator
@ Add 105 ml (3.5 fl. 02.) to new
accumulator
C. Evaporator
@ Add 90 ml (3 fl. oz.) oil
D. Condenser
@ Add 30 ml (1 fl. 02.) oil
Refrigerant oil loss due to a large leak
If the refrigerant charge is aburptly lost due to a
large refrigerant leak, approximately 90
ml (3 fl. oz.)
of refrigerant oil will be
carried out of the system sus-
pended in the refrigerant. Any failure that caused an
abrupt refrigerant discharge will experience this oil
loss. Failures that allow the refrigerant to seep or
bleed off over time do not experience this oil loss.
Upon replacement of a component which
caused a large refrigerant leak, add 90 ml(3
fl. oz.) of
new 525 viscosity refrigerant oil plus the required
amount of oil for the particular component (as out-
lined above).
Add the oil directly to the replaced component if
possible. If the oil cannot easily be added to the
replaced part, add the oil to the accumulator.
Evacuating and Charging the A/C System
If the system has been opened for any repair, or
the Refrigerant-12 charge lost, the system must be
evacuated prior to charging.
Evacuating and charging is a combined proce-
dure, and all gauge lines must be purged with R-12
prior to charging.
There are three evacuate and charge procedures.
1.
J 23500-01 Charging Station Method
2. Disposable Can Method 3. Drum Method
NOTICE: Under no circumstances should alco-
hol be used in the system in an attempt to remove
moisture. Damage to the system components
could occur.
Gauge Calibration
Prior to evacuation, check the low-pressure
gauge for proper calibration and determine if vacuum
system is operating properly.
With the gauge disconnected from the refrigera-
tion system, be sure that the pointer indicates to the
center of
"0". Lightly tap gauge a few times to be sure
pointer is not sticking. If necessary, calibrate as
follows:
1. Remove cover from gauge.
2. Holding gauge pointer adjusting screw firmly
with one hand, carefully force pointer in the
proper direction to position pointer at the
"0"
position. Tap gauge a few times to be sure
pointer is not sticking. Replace gauge cover.
Vacuum System Check
Before connecting vacuum pump to the A/C
system, run pump connected to the low-pressure
gauge to determine the vacuum pump capability. If
the vacuum system is unable to reach
7 1 1.2-736.6mm
(28"-29") or more vacuum, the system should be
checked for leaks. If no leaks are found, the vacuum
pump may require repair.
5-23580-81 OR EQUIVALENT CHARGING
STATION METHOD.
Follow charging instructions provided with the
5-23500-01 Charging Station or equivalent in use with
the following exceptions:
1. Do
not connect the high-pressure line to the air
conditioning system.
2. Keep the high-pressure valve on the charging
station closed at all times.
3.
Perform the entire evacuate and charge proce-
dure through the accumulator low-side pressure service fitting.
4. Following these procedures will prevent acci-
dental high-side vehicle system pressure being
subjected to the charging station in the event an
error is made in valve sequence during compres-
sor operation to pull in the Refrigerant-12
charge.
DISPOSABLE CAN OR REFRIGERANT
DRUM METHOD.
If the Refrigerant-12 drum is used, place it on a
scale and note the total weight before charging. Watch
the scale during charging to determine the amount of
R-12 used.
If disposable
420ml (14 ounce) R-12 cans are
used, close the tapping valve and then attach
can(s)
following instructions included with the tapping valve
or tapping manifold adapter.
1. Connect manifold gauge set 5-23575-01 as fol-
lows. Also see Figure 16.
a. Eow-pressure gauge to accumulator fit-
ting.
b. Gauge set center hosk to Refrigerant-12
source.
c. High-pressure gauge to vacuum pump.
2. To begin evacuation of the
A/C system with
manifold gauge set and vacuum pump as illus-
trated in Figure 16, slowly open
high- and low-
side gauge valves and begin vacuum pump oper-
ation. Pump the system until the low-side gauge
reaches 7 1
1.2-736.6mm (28"-29") vacuum.
Note that in all evacuation procedures, the spec-
ification of 7 1
1.2-736.6mm (28"-29") vacuum is
used. This specification can only be reached at
or near sea level. For each
304.8m (1,000 feet)
above sea level, specification should be lowered
by one inch vacuum. At
1524m (5,000 feet)
elevation, only
584.2-609.6mm (23"-24") of
vacuum is required.

AIR CONDITIONING 1B-17
If prescribed vacuum cannot be reached, close
vacuum control valve, shut off pump and look
for a leak at connections or pump.
3. When gauge reaches prescribed vacuum, the
system is fully evacuated. Close the high-side
gauge set valve and turn off the vacuum pump.
4. Watch low-side gauge to be sure vacuum holds
for five (5) minutes. If vacuum is held, discon-
nect vacuum hose at gauge set and then proceed
to charging.
5. If vacuum does not hold for five (5) minutes,
charge system with
420ml(1/2 pound) Refriger-
ant-12 and leak check. Discharge system again
and repair leak as necessary. Repeat evacuation
procedure.
To Begin Charging of the NC System
1. Start engine and set A/C mode control button on
"OFF. "
2. With the Refrigerant-12 drum or 420ml (14
ounce)
can(s) inverted, open R-12 source
valve(s) and allow 480ml (1 pound) or one
420m1 (14 02.) can of liquid R-12 to flow into
system through low-side service fitting.
3. As soon as 480ml (1 lb.) or one 420ml (14 oz.)
can of R-12 has been added to system, immedi-
ately engage the compressor by setting the
A/C
control button to NORM and blower speed on
HI, to draw in the remainder of the R-12 charge.
See specifications for total R-12 charge. The
charging operation can be sped up by using
a large volume fan to pass air over the con-
denser. If condenser temperature is maintained
below charging cylinder temperature,
Refriger-
ant-12 will enter the system more rapidly.
4. Turn off
R-12 source valve and run engine for
30 seconds to clear lines and gauges.
5. With the engine running, remove the charging
low-side hose adapter from the accumulator ser-
vice fitting. Unscrew rapidly to avoid excess
R-12 escape from system.
CAUTION: NEVER REMOVE A GAGE
LINE FROM ITS ADAPEER WHEN LINE
IS CONNECTED TO A/G SYSTEM.
ALWAYS REMOVE
THE LINE ADAPTER
FROM THE
SERVICE F1miNG TO DIS-
CONNECT A LINE. DO
NOT REMOVE
CHARGING
HOSE AT GAGE SET WHILE
ATTACHED TO ACGUMULBTOR. "THIS
WILL RESULT IN COMPLETE DIS-
CHARGE OF SYSTEM DUE TO THE
DEPRESSED SCHRADER VALVE IN
SERVICE LOW-SIDE
F17$TING, AND MAY
CAUSE PERSONAL
INJURY DUE TO
ESCAPING REFRIGERANT-72;.
6. Replace protective cap on accumulator fitting.
7. Turn engine off.
8. Leak check system with electronic leak detector
5-29547 or equivalent (see Diagnosis).
9. Start engine.
10. With system fully charged and leak-checked,
continue to operate system performance.
THIS HI-PRESS. VALVE IS
EVACUATION
ACCUMULATOR
ISPENSING UNIT
30 LB. DRUM HAS
OWN OPENER-VALVE
WARNING: MAKE SURE OUTLET VALVE
ON OPENER IS CLOSED (CLOCKWISE)
R-12 CQNTAINER.
OPEN AND INVERTED
DURING CHARGING
EVACUATION
Figure 16 Charging the System With Disposable Can or Drum

AIR CONDITIONING 18-19
3. Push the tube into the fitting, bottoming it out.
Tighten
@ Torque nut to 15 Nam (11 lbs. ft.).
4. Dissasemble the joint.
5. Lubricate the
"0" ring with clean 525 viscosity
refrigerant oil.
6. Install the
"0" ring
on the tube. (See figure 17b)
7. Reassemble joint.
Tighten
@ Torque nut to 15 Nem (11 lbs. ft.).
8. Evacuate, charge, and leak test the system.
EXPANSlON "%BE (ORIFICE) SERVlCE
Remove or Disconnect
1. Discharge system.
2. Loosen fitting
at liquid line to evaporator inlet
pipe and remove tube carefully with needle
nosed pliers or Tool
5-26549-C or equivalent.
Install or Connect
1. Install
new orifice tube with shorter screen end
in first.
2. Install
liquid line and torque to proper
specification.
3. Evacuate and charge system.
In the event that difficulty is encountered during
the removal of a restricted or plugged expansion tube
(orifice tube), the following procedure is recom-
mended:
1. Remove
as much of any impacted residue as
possible.
2. Carefully apply heat with heat gun (hair drier,
epoxy drier or equivalent) approximately
114
inch from dimples on inlet pipe. Do not over-
heat pipe.
NOTICE: If the system has a pressure switch
near the orifice tube location, it should be
removed prior to heating the pipe to avoid dam-
age to switch.
3. While applying heat, use orifice removal tool
5-26549-C to grip the orifice tube. Use a turning
motion along with a push-pull motion to loosen
to the impacted orifice tube and remove it.
4. Swab inside of evaporator inlet pipe with R-11.
5, Add
1 oz. of 525 viscosity refrigerant oil to
system.
6. Lubricate new orifice tube and O-ring with 525'
viscosity refrigerant oil and insert into inlet
pipe. Install in proper direction (smaller screen
first).
ACCUMULATOR ASSEMBLY SERVICE
The accumulator assembly for the refrigerant
system has a service replacement which includes two
(2) O-rings (for the inlet and outlet connections). The
desiccant within the shell is NOT serviced separately
- it is part of the sealed accumulator assembly. See
REFRIGERANT OIL DISTRIBUTION for condi-
tions when the accumulator must be removed from the
vehicle to measure the amount of oil present inside the
accumulator.
The accumulator assembly should ONLY be
replaced when:
1. A physical perforation to the accumulator is
found, resulting in a leak.
2. If the system is open to air for an extended
period of time (due to a front-end collision,
removed parts, ect.). The desiccant bag will be
saturated with moisture.
1 -ACCUMULATOR 9-CORE & CASE
2-EVAPORATOR BLOWER ASSEMBLY
10-A/C AIR
3-EVAPORATOR CORE 11-BI-LEVEL
4-BLOWER ASSEMBLY 5-AIR INLET ASSEMBLY
'IR
6-OUTSIDE AIR 13-DEFROST
AIR
7-INSIDE
AIR 14-SIDE WINDOW
DEFOG AIR
8-HEATER CORE
Figure 18 Functional Components

18-28 AIR CONDITIONING
DO NOT REPLACE the accumulator assembly
when:
1. Merely a dent is found in the outer shell of the
accumulator.
2. A
vehicle is involved in a collision and no phys-
ical perforation to the accumulator is found.
OM-VEHICLE SERVICE
R-"1 CHARGING CAPACITIES
The 420ml (14 fl. oz.) disposable can of R-12
refrigerant is equivalent to .399 kg (. 88 lb.).
BLOWER MOTOR
a Remove or Disconnect
1. Disconnect negative battery cable.
2. Remove motor cooling tube.
3. Disconnect electrical connections.
4. Remove blower motor attaching screws, remove
motor and case assembly.
5. Loosen retaining nut and remove blower cage
from motor shaft.
6. Inspect blower cage for broken vanes, etc.
Replace if necessary.
Install or Connect
1. Reverse removal procedure to reinstall. Replace
seals or sealant as required.
HI-BLOWER RELAY
Relay is a plug-in type with connector mounted
on top of the evaporator case.
BLOWER RESISTOR
Remove or Disconnect
1. Disconnect negative battery cable.
2. Disconnect electrical connections.
3. Remove two (2) screws, remove resistor.
Install or Connect
1. Reverse removal procedure to reinstall.
CONTROLLER, BLOWER SWITCH OR
WCUUM VALVE
Remove or Disconnect
1. Disconnect negative battery cable.
2. Remove NC control-radio console trim plate.
3. Remove three (3) NC control retaining screws.
4. Pull A/C control out and disconnect electrical
and vacuum connections and remove tempera-
ture cable.
5. Remove A/C control and replace vacuum valve
or blower switch as required.
Install or Connect
1. Reverse removal procedure to reinstall. Install
lower right screw in controller first to align con-
troller in console.
TEMPERATURE CONTROL CABLE,
VACUUM HARNESS
Remove or Disconnect
1. Remove the following hush panel(s):
a. Vacuum Harness - R.H. and L.H. hush
panel.
b. Temperature Cable
- R.H. hush panels.
Remove
controller/radio console trim plate.
Remove three (3) controller screws and pull
controller partially out of console.
Disconnect controller
end(s) of temperature
cable
andlor vacuum harness.
Disconnect component
end(s) of temperature
cable
andlor vacuum harness.
Install or Conned
1. Reverse removal procedure to reinstall. When
installing controller, install lower right screw
first to align controller location. Replace any
retaining straps, etc. removed.
2. Perform functional check of controller.
CONTROL WlRlNG HARNESS
a Remove or Disconnect
1. Disconnect negative battery cable.
2. Remove
control/radio console trim plate and
hush panels (see Section
8C).
3. Remove three (3) screws holding control in con-
sole and pull control out far enough to discon-
nect electrical and vacuum connector. Remove
controller.
4. Remove instrument panel carrier (see Section
8C).
5. Remove heater case covers (core and mode door
sides).
6. Remove two (2) interior screws and one (1)
exterior nut holding case to cowl. Pull left side
of case back to gain access to harness at cowl.
Case will still be retained by one (I) screw
behind the evaporator core
- do not attempt
complete removal of case. -
7. Loosen cowl grommet and disconnect purple
vacuum line.

AIR CONDITIONING 18-21
8. Disconnect blower motor
and blower resistor
electrical connection.
9. Remove hi-blower relay connector from evapo-
rator case.
10. Carefully pull
cowl grommet from cowl and pull
wiring
hmess into engine compartment.
Install or Connect
1. Reverse removal procedure to
reinstall. When
reinstalling controller, install lower right screw
first to align controller.
ACNENTILATIONIDEFROSVER DUCTS
See section 8C for removal.
HEATER CORE
Remove or Disconnect
1. Negative battery cable.
2. Drain cooling system.
3. Remove heater inlet and outlet hoses
from
heater core.
4. Remove right lower hush panel (see Section
8C).
5. Remove right
lower I.P. trim panel (see Section
8C) .
6. Remove lower right I.P. carrier to cowl screw.
7. Remove ECM attaching screws and move to the
side.
8. Remove four
(4) heater case cover screws.
Upper left screw may be reached with a long
318 ' socket extension through the I.P. openings
exposed by removal of the lower right I.P. trim
panel. Carefully lift the lower right corner of the
I.P. to align socket extension.
9. Remove heater case cover.
10. Remove core support plate
and baffle screws.
- -
11. Remove
heater core, support plate and baffle
from case.
Install or Conned
1. Reverse removal procedure to reinstall. Restore
all seals
and/or sealant disturbed during removal
procedure.
2. Refill cooling system and check for leaks.
LOWER (FLOOR) )-IEA"FEB$OU"fET
Remove or Disconnect
1. Console. (See Section 8C.)
2. L.H. and R.H. hush panels.
3. Two (2) floor outlet retaining screws.
4. Floor outlet from core case.
lnstall or Connect
1. Floor outlet to core case.
2. Two (2) floor outlet retaining screws.
3. L.H. and R.H. hush panels.
4. Console.
HEATER MODULE (CASE)
Remove or Disconnect
1. Disconnect negative battery cable.
2. Drain cooling system.
3. Remove hush panels and instrument panel car-
rier (see Section
8C).
4. Remove lower heater outlets.
5. Disconnect control cables and vacuum hoses at
module and controller.
6. Remove heater core.
7. Remove two (2) interior screws and one (I)
exterior nut holding case to cowl.
8. Remove evaporator core.
9. Remove screw holding case to cowl from engine
compartment side.
10. Remove case (module).
11. Transfer usable parts to new case (module).
lnstall or Conned
1. Reverse removal procedure to reinstall.
2. Refill coolant system.
3. Recharge
A/C system.
4. Inspect A/C and cooling system for leaks.
NC PRESSURE CYCLING SWITCH
Do not discharge A/C system. Pressure cycling
switch is mounted on
a Schrader-type valve.
Remove or Disconnect
1. Disconnect switch electrical connection.
2. Remove switch.
Install or Connect
1. Reverse removal procedure to reinstall. Tighten
switch to
4-5.5 N*m (35-49 in. lb.).
Ale CONTROL VACUUM TANK
Remove or Disconnect
1 . Disconnect vacuum hoses.
2. Remove vacuum
tank attaching screws, remove
tank.
lndall or Connect
1. Reverse removal procedure to
reinstall.

1B-22 AIR CONDITIONING
HEATER UPPER MODE CLOSED
POSITION DOOR POSITION POSITION
I SIDE WINDOW DEFOG
DEFROSTER
A BLEED
HEATER AIR
OFF AND HEATER MODES
SlDE WINDOW DEFOG
HEATER AIR
BI-LEVEL MODE FULL
COLD POSITION
FULL HOT POSITION
(ALL AIR AROUND
(ALL AIR THROUGH
HEATER CORE) HEATER CORE)
TEMPERATURE
TEMPERATURE
COlUTROL
MAX,NORM AND VENT MODES
SlDE WINDOW DEFOG
DEFROSTER AIR
HEATER BLEED
DEFROST MODE
5201 26-1 8
Figure 19 Air Flow Direction In Each Operating Mode

AIR CONDITIONING "18-23
10. CONTROL
14. LOWER MODE
DIAPHRAGM
16. DEFROST DIAPHRAGM
17. UPPER MODE
DIAPHRAGM
18. RECIRCULATION
5. TO WATER VALVE 19. lfVPUT (VIOLET)
6. A/C ELECTRICAL 20. DEFROST (BLUE)
21. LOWER MODE (TAN)
22. UPPER MODE (RED)
8. RECIRCULATION
DIAPHRAGM J~OZ~~-IB-F
Figure 20 AIC Vacuum Diagram
NG LlCbUlB LINE
Remove or Disconnect
1. Discharge A!C system.
2. Disconnect liquid line couplings at evaporator
and condenser connections.
3. Remove clip holding line to right frame rail.
4. Remove liquid line.
lnstall or Conne&
1. Reverse removal procedure to reinstall. Use
new O-rings lubricated with
525 viscosity
refrigerant oil.
2. Recharge and test system for proper operation.
COUPLED NC HOSE ASSEMBLY
Remove or Disconne&
lnstall or Conne&
1. Reverse removal procedure to reinstall. Use
new O-rings lubricated with
525 viscosity
refrigerant oil.
2. Recharge and test system for proper operation.
Remove or Disconnect
1. Discharge A!C system.
2. Disconnect electrical connection at pressure
cycling switch and remove switch.
3. Disconnect hose and evaporator fittings.
4. Loosen accumulator clamp-bracket screw.
5. Remove accumulator.
1. Discharge
NC system.
2. Disconnect hose assembly at accumulator, con- Install or Connect
denser, and at rear of c6mpressor head. 1. Reverse removal procedure to reinstall. Use
3. Disconnect clamps or straps that hold hose new
O-rings lubricated with 525 viscosity
assembly in position if so equipped, remove refrigerant
oil.
coupled hose assembly.
2. Recharge and test system for proper operation.

1B-26 AIR CONDITIONING
7-FITTING (ENGINE)
13-PIPE ASM - INLET & 8-PIPE ASM - HTR INLET
OUTLET
9-A.I.R. PUMP BRACKET 14-GENERATOR
10-HOSE
- HTR OUTLET
15-GEN BRACKET 11-AIC EVAP TUBE ASM 16-GASKET
12-HOLES (SIDE RAIL)
Figure 23 NC Heater Hoses - V.I.N. S
2. A.I.R. VALVE
3. WATER VALVE
4. RADIATOR
5. AIC EVAPORATOR TUBE
Figure 24 NC Heater Hoses - V.I.N. E