Section 12-00: Climate Control System, Service | 1996 F-150, F-250, F-350, F-Super Duty and Bronco, F-Super Duty Motorhome Chassis Workshop Manual |
SERVICE PROCEDURES
A/C System Check — Retail Procedure
NOTE: This Retail Procedure is not eligible for claiming on Ford paid repairs (warranty and ESP).
WARNING: CARBON MONOXIDE IS COLORLESS, ODORLESS AND DANGEROUS. IF IT IS NECESSARY TO OPERATE THE ENGINE WITH THE VEHICLE IN A CLOSED AREA SUCH AS A GARAGE, ALWAYS USE AN EXHAUST COLLECTOR TO VENT THE EXHAUST GASES OUTSIDE THE CLOSED AREA.
WARNING: R-134A IS CLASSIFIED AS A SAFE REFRIGERANT, BUT MISUSE CAN MAKE IT DANGEROUS. THE FOLLOWING PRECAUTIONS MUST BE OBSERVED:
- ALWAYS WEAR SAFETY GOGGLES WHEN REPAIRING AN AIR CONDITIONING SYSTEM.
- AVOID CONTACT WITH LIQUID R-134A. R-134A VAPORIZES AT APPROXIMATELY -25 DEGREES C (-13 DEGREES F) UNDER ATMOSPHERIC PRESSURE AND IT WILL FREEZE SKIN TISSUE.
- NEVER ALLOW REFRIGERANT R-134A GAS TO ESCAPE IN QUANTITY IN AN OCCUPIED SPACE. R-134A IS NON-TOXIC, BUT IT WILL DISPLACE THE OXYGEN NEEDED TO SUPPORT LIFE.
- NEVER USE A TORCH IN AN ATMOSPHERE CONTAINING R-134A GAS. R-134A IS NON-TOXIC AT ALL NORMAL CONDITIONS, BUT WHEN IT IS EXPOSED TO HIGH TEMPERATURES, SUCH AS A TORCH FLAME, IT DECOMPOSES. DURING DECOMPOSITION IT RELEASES IRRITATION AND TOXIC GASES (AS DESCRIBED IN THE MSDS SHEET FROM THE MANUFACTURER). DECOMPOSITION PRODUCTS ARE HYDROFLUORIC ACID, CARBON DIOXIDE, AND WATER.
- DO NOT ALLOW ANY PORTION OF THE CHARGED AIR CONDITIONING SYSTEM TO BECOME TOO HOT. THE PRESSURE IN AN AIR CONDITIONING SYSTEM RISES AS THE TEMPERATURE RISES AND TEMPERATURES OF APPROXIMATELY 85 DEGREES C (185 DEGREES F) CAN BE DANGEROUS.
- ALLOW THE ENGINE TO COOL SUFFICIENTLY PRIOR TO CARRYING OUT MAINTENANCE OR SERIOUS BURNS AND INJURY CAN OCCUR.
WARNING: AVOID CONTACT OF LIQUID R-12 WITH SKIN AND EYES. AT NORMAL ATMOSPHERIC PRESSURES AND TEMPERATURES, R-12 EVAPORATES SO QUICKLY THAT IT HAS THE TENDENCY TO FREEZE ANYTHING IT CONTACTS. SHOULD LIQUID REFRIGERANT COME IN CONTACT WITH THE EYES, IMMEDIATELY WASH WITH A FEW DROPS OF MINERAL OIL FOLLOWED BY A WEAK BORIC ACID SOLUTION. CONTACT A PHYSICIAN IMMEDIATELY.
WARNING: ALWAYS WEAR SAFETY GOGGLES WHEN SERVICING ANY PART OF THE REFRIGERANT SYSTEM. R-12 IS ALWAYS UNDER PRESSURE. BECAUSE THE SYSTEM IS TIGHTLY SEALED, HEAT APPLIED TO ANY PART OF THE SYSTEM WILL CAUSE EXCESSIVE PRESSURE BUILDUP. TO AVOID A DANGEROUS EXPLOSION, NEVER WELD, USE A BLOW TORCH, SOLDER, STEAM CLEAN, BAKE BODY FINISHES OR USE AN EXCESSIVE AMOUNT OF HEAT ON OR IN THE IMMEDIATE AREA OF ANY PART OF THE AIR COOLING SYSTEM OR REFRIGERANT SUPPLY TANK, WHILE CLOSED TO ATMOSPHERE, WHETHER FILLED WITH REFRIGERANT OR NOT.
WARNING: LIQUID REFRIGERANT EVAPORATES RAPIDLY, DISPLACING AIR WHERE THE REFRIGERANT IS RELEASED. TO PREVENT POSSIBLE SUFFOCATION IN ENCLOSED AREAS, DISCHARGE THE REFRIGERANT FROM AN AIR COOLING SYSTEM INTO THE GARAGE EXHAUST COLLECTOR. MAINTAIN GOOD VENTILATION SURROUNDING THE WORK AREA.
WARNING: ALTHOUGH R-12 GAS, UNDER NORMAL CONDITIONS, IS NON-POISONOUS, THE DISCHARGE OF REFRIGERANT GAS NEAR AN OPEN FLAME CAN PRODUCE A VERY POISONOUS GAS. IT IS GENERATED WHEN THE FLAME-TYPE LEAK DETECTOR IS USED. AVOID INHALING FUMES FROM THE LEAK DETECTOR. MAKE CERTAIN THAT R-12 IS STORED AND INSTALLED IN ACCORDANCE WITH ALL STATE AND LOCAL ORDINANCES.
CAUTION: To avoid damaging the vehicle or A/C components, the following precautions must be observed:
- The A/C refrigerant of all vehicles must be identified and analyzed prior to refrigerant charging. Failure to do so can contaminate the shop bulk refrigerant and other vehicles.
- Do not add R-12 refrigerant to an A/C system that requires the use of R-134a refrigerant. These two types of refrigerant must never be mixed. Doing so can damage the A/C system.
- Charge the A/C system with the engine running only at the low-pressure side to prevent refrigerant slugging from damaging the A/C compressor.
- R-134a must not be mixed with air for leak testing or used with air for any other purpose above atmospheric pressure. R-134a is combustible when mixed with high concentrations of air and higher pressures.
- A number of manufacturers are producing alternative refrigerant products that are designed to be used instead of R-134a refrigerant. The use of any unauthorized substitute refrigerant can severely damage the A/C components. If repair is required, use only new or recycled refrigerant R-134a.
CAUTION: To avoid contamination of the A/C system, always observe the following:
- Keep service tools and the work area clean.
- Never open or loosen a connection before discharging the system.
- When loosening a connection, if any residual pressure is evident, allow it to leak out before opening the fitting.
- Evacuate a system that has been opened to install a new component or one that has been discharged through leakage before charging.
- Seal an open fitting with a cap or plug immediately after disconnecting a component from the system.
- Clean the outside of the fittings thoroughly before disconnecting a component from the system.
- Do not remove the sealing caps from a new component until ready to install.
- Refrigerant oil will absorb moisture from the atmosphere if left uncapped. Do not open an oil container until ready to use, and install the cap immediately after using. Store the oil in a clean, moisture-free container.
- Install a new O-ring seal before connecting an open fitting. Coat the fitting and the O-ring seal with refrigerant oil before connecting.
- When installing a refrigerant line, avoid sharp bends. Position the line away from the exhaust or any sharp edges that can chafe the line.
- Do not open a refrigerant system or uncap a new component unless it is as close as possible to room temperature. This will prevent condensation from forming inside a component that is cooler than the surrounding air.
CAUTION: A number of manufacturers are producing refrigerant products which are described as being direct replacements for R-12. The use of any unauthorized substitute refrigerant may severely damage the A/C components. If service is required, use only new or recycled R-12.
NOTE: The engine should be run at idle for 10 minutes with the air conditioning on and set to MAX A/C before carrying out this retail procedure.
Visual inspection
Open the hood and visually inspect the heating and air conditioning systems for the following:
- Coolant reservoir for correct coolant level.
- Heater hoses for deterioration or loose connections.
- Radiator and condenser for debris or damaged fins restricting airflow, loose mounting or connections.
- Accessory drive belt(s) and cooling fan(s) for wear or physical damage.
- Refrigerant lines and connections for physical damage or loose connections.
- Compressor for physical damage or loose connections.
- Suction accumulator/drier for physical damage or loose connections.
- Wiring and connectors for excessive wear, loose or damaged connections, or incorrect routing.
A/C refrigerant analysis
- Carry out air conditioning refrigerant analysis as outlined in TSB # 98-12-08.
- If the refrigerant fails the analysis, discontinue diagnosis and make recommendations for repairs.
- If the refrigerant passes the analysis, carry out the air conditioning system check.
Air conditioning system check
- Connect manifold gauge set or charging station with gauges to refrigerant system.
- With the vehicle in park, parking brake set, thermometer installed in center panel vent, and air conditioning system on and set to MAX A/C, start the engine.
- Record air refrigerant system pressures while running the engine at 1500 RPM and allow engine to return to idle.
- Operate the blower motor in all control positions and check for correct blower speed changes.
- With the blower motor on HI, operate air discharge mode selector in all positions and check for correct airflow in each position.
- Operate the temperature blend selector in all positions and check for correct change in discharge temperature.
Check the air discharge temperature with the selector in the coolest position and the air conditioning on and set to MAX A/C to determine if the air discharge temperature is acceptable for the current ambient air temperature.
- Carry out the EATC self-test (if applicable).
If the refrigerant system pressures were low, carry out the refrigerant system leak test.
Refrigerant system leak test
- Pre-1995 vehicles - Use an electronic leak detector to check for leaks at all refrigerant lines, connections, and components.
- 1995 and newer vehicles - Use either an ultraviolet (UV) or an electronic leak detector to check for leaks at all refrigerant lines, connections, and components.
After all tests have been completed, report all findings and recommended repairs to your service advisor before carrying out further diagnostic procedures.