1990 VOLKSWAGEN CORRADO heater

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 2)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
Temperature Control Lever
The temperature control lever controls heating and cooling.
When moved to the left, lever turns compressor on. When moved to the
right, a heater water valve is opened, supplying coolant to heater
core.
HIGH-PRESSURE SWITCH
High-pressure switch shuts compressor off if high pressure
reaches 210 psi (14.8 kg/cmý). High-pressure switch will reset when
pressure decreases to 174 psi (12.2 kg/cm
ý).
LOW-PRESSURE SWITCH
Low-pressure switch cuts off system operation when there is
abnormally low pressure in system. This protects the compressor when
there is not enough R-12 in system. Low-pressure switch shuts
compressor off at 26 psi (1.8 kg/cm
ý).
THERMOSWITCH
Thermoswitch shuts compressor off if coolant temperature
rises above 248
øF (120øC).Fig. 1: Locating A/C Components (Vanagon)
Courtesy of Volkswagen United States, Inc.

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 3)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PMFig. 2: Exploded View of Manual A/C-Heater System Components
(Cabriolet)
Courtesy of Volkswagen United States, Inc.

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 4)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PMFig. 3: Exploded View of Manual A/C-Heater System Components (Fox
& Fox Wagon)
Courtesy of Volkswagen United States, Inc.
SERVICING PRECAUTIONS
WARNING: Cabriolet is equipped with a driver's side air bag. Air bag
equipped vehicles have AIRBAG stamped on the steering wheel
horn pad. The air bag system capacitor maintains a voltage
charge sufficient to cause air bag deployment for up to 20
MINUTES after ignition switch is turned off and battery is
disconnected.
AIR BAG DEACTIVATION - CABRIOLET
Disabling System
Ensure ignition switch is OFF. Disconnect negative battery
cable and insulate terminal. Wait at least 20 MINUTES before servicing
vehicle.
System Functional Check
When all service work is completed, reconnect negative
battery cable. Turn ignition on. Ensure LEFT air bag indicator light
(above air bag symbol) comes on for about 5 seconds and then goes out.
If left air bag indicator light does not operate as indicated, air bag
system needs to be serviced.
ADJUSTMENTS

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 5)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
MICROSWITCH
Loosen microswitch mounting screw. Move microswitch so switch
is on when lever is at maximum A/C, NORM (normal), BI-LEVEL or extreme
right position, and off when lever is at VENT or HEAT position.
Tighten microswitch mounting screw. Recheck operation.
TEMPERATURE SWITCH
Move temperature lever to full cool position. Loosen
temperature switch mounting screw. Move temperature switch
counterclockwise to full stop position. Tighten temperature switch
mounting screw.
TROUBLE SHOOTING
NO COOLING
1) Ensure fan motor operates in all 4 speeds, air duct closes
off outside air and heater water valve is closed. Adjust belt tension.
2) Inspect receiver-drier pressure seal. If seal is good, go
to step 5). If seal is broken, evacuate and recharge system. If system
cools properly, testing is complete. If system does not cool, connect
pressure gauges.
3) Set engine speed at 2500 RPM. Insert thermometer in left
register and close all others. Place controls on high blower and
maximum cooling. With vehicle out of direct sunlight, close all
windows. Radiator fan should come on with system pressure at 200 psi
(14 kg/cmý).
NOTE: If system doors allow air leaks, evaporator will freeze up
and testing will not be possible.
4) If fan does not operate, replace pressure switch. Ensure
system is okay. If fan does come on, turn engine off and check for
condenser obstructions and blocked airflow.
5) Turn air conditioner on and off with temperature control
lever. Ensure compressor clutch engages. Push lever to extreme right
position and back again. A click should be heard from compressor
clutch. If a click is not heard, check for voltage at clutch coil wire
with switch on. If voltage is present, replace clutch coil. If voltage
is not present, check wiring or replace thermostatic switch.
6) If compressor clutch operates, check gauge readings. If
both are low, locate leak and recharge system. If both are high,
replace expansion valve. If low side is too high and high side reads
too low, replace or rebuild compressor.
INSUFFICIENT COOLING
1) Ensure fan motor operates at all 4 speeds, air duct closes
off outside air intake and heater water valve is closed. Adjust
compressor belt tension and clean condenser.

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 6)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
NOTE: If system doors allow air leaks, evaporator will freeze up
and testing will not be possible.
2) Adjust engine speed to 2500 RPM. Position controls for
maximum cooling and high blower. Insert thermometer in left register
and close all other ducts. With vehicle out of sun, close all windows
and doors. Connect pressure gauges and check readings.
3) If both gauges read too high, replace expansion valve. If
both read too low, recharge system after locating leak. If both
readings are normal, go to next step. If pressure side is too high and
suction side is normal, go to step 5). If pressure side is too low and
suction side is too high, go to step 6). If pressure side is normal
and suction side is too low, go to step 7).
4) Turn compressor off and observe gauges. If readings
equalize in 30 seconds, replace compressor. If readings take longer to
equalize, ensure capillary installation in evaporator is 7" (178 mm)
long on all models.
5) If installation is correct, run system at maximum cooling
for 15 minutes. If thermometer indicates temperature below 36øF (2øC)
when compressor is turned off, or temperature is above 48
øF (9øC) with
compressor on, replace temperature switch.
6) Check condenser fins and clean or straighten. If operation
is still not correct, discharge system, using approved refrigerant
recovery/recycling equipment, until bubbles show in sight glass.
Recharge until bubbles disappear, and recheck pressures. If still
incorrect, locate leaks and tighten fittings. Discharge system using
approved refrigerant recovery/recycling equipment. Evacuate to remove
all air and recharge system.
7) Check for bubbles at sight glass. If present, repair leaks
and recharge system. If no bubbles are present, check condenser-to-
expansion valve line for kinks and repair if necessary. Feel along
line from condenser to expansion valve. If there are no cold spots,
replace expansion valve.
8) If cold spot is felt, remove and flush out lines and
condenser. Check for bubbles at sight glass. If there are no bubbles
present, replace compressor. If bubbles are present, check for leaks.
Repair and recharge system.
INTERMITTENT COOLING
1) Ensure fan motor operates in all 4 speeds, air duct closes
off outside air and heater water valve is closed. Adjust belt tension
and clean condenser.
NOTE: If system doors allow air to leak by, evaporator will freeze
up and testing will no longer be possible.
2) Adjust engine speed to 2500 RPM. Set controls for maximum
cooling and high fan. Insert thermometer in left air duct and close
all other ducts. With vehicle under shade, close windows and doors and
connect pressure gauges. Operate system for 10 minutes.

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 7)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
3) Check for cool air from left duct. Low-pressure gauge
should read more than 16 psi (1.1 kg/cmý). If low-pressure gauge is
incorrect, hold hands around expansion valve to warm valve. If
pressure rises, moisture is present in system. Discharge using
approved refrigerant recovery/recycling equipment. Evacuate and
recharge system. If pressure does not rise, go to next step.
4) Check temperature on thermometer when thermostatic switch
turns compressor off. If temperature is 39
øF (4øC), system is okay. If
lower than 39
øF (4øC), ensure capillary tube installed length is 7"
(178 mm). If installation is correct, replace thermostatic switch.
REMOVAL & INSTALLATION
NOTE: Removal and installation procedures on other models or
components are not available from manufacturer.
EVAPORATOR - VANAGON
1) Discharge refrigerant from system using approved
refrigerant recovery/recycling equipment. Remove sun visors and sun
visor retaining clips. Lower front housing and front air duct.
2) Disconnect wiring connectors to A/C switches. Remove front
housing, front air ducts, center air duct, rear air duct, left side
rear trim panel and right side rear trim panel.
3) Support evaporator housing. Remove left and right side
evaporator housing mounting screws. Lower evaporator housing. Remove
evaporator housing covers. Remove evaporator. See Fig. 4. To install,
reverse removal procedure. Evacuate and recharge system.Fig. 4: Exploded View of Evaporator Assembly (Vanagon)
Courtesy of Volkswagen United States, Inc.
A/C SYSTEM SPECIFICATIONS

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 8)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
A/C SYSTEM SPECIFICATIONS TABLEÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄApplication Specification
System Type ............................... Cycling Clutch
Compressor Type ........................ Sanden 5-Cylinder
Compressor Oil Capacity
Cabriolet ...................................... 6.0 oz.
Fox ............................................ 1.4 oz.
Compressor Belt Deflection
All Models .......................... (1) 3/16" (4.8 mm)
System Oil Capacity
Vanagon ........................................ 5.0 oz.
All Others ..................................... 4.6 oz.
Refrigerant (R-12) Capacity
Corrado ...................................... 37-40 oz.
Vanagon ......................................... 50 oz.
All Other Models ............................. 38-40 oz.
System Operating Pressures
Low Side ........................ 26-40 psi (1-2 kg/cm
ý)
High Side ................. 150-210 psi (10.5-19 kg/cm
ý)
(1) - Deflection is measured at center of belt, between
A/C compressor pulley and crankshaft pulley.
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ WIRING DIAGRAMS

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 9)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PMFig. 5: Manual A/C-Heater System Wiring Diagram (Cabriolet)