Heating, Ventilation & Air Conditioning: Other GMC Yukon Denali

GM SPO Group Numbers

GM SPO Group Numbers

Electronic Leak Detector

Tools Required

J 39400 Electronic Leak Detector. See Special Tools .

Scheme 17

This type of leak detector is the most useful tool in locating refrigerant leaks. The J 39400 is a small unit that operates on 12V DC. See Special Tools . The J 39400 provides an audible signal that increases in frequency as R-134a is detected. Ensure that the instrument is properly calibrated in accordance with the included instructions. Use the detector in the proper setting for the type of refrigerant being tested. Place the detector GAS switch in the R-134a setting prior to use.

The most common leaks are found at the refrigerant fittings or connections. The causes of common leaks may be the following conditions

1. Improper torque
2. Damaged O-ring sealing washers.
3. Dirt and debris across the O-ring sealing washers.

Even the smallest piece of lint from cotton gloves or shop cloths can create a leak path across an O-ring sealing washers.

Scheme 18

The successful use of this and any other electronic leak detector depends greatly upon the scan rate. The successful use of the detector depends upon the carefully following the manufacturer's instructions regarding calibration, operation and maintenance.

Scheme 19

Circle each joint completely. Move the probe at 25-51 mm (1-2 in) per second. Move the tip of the probe as close to the surface as possible, but no more than 6 mm (0.25 in) away. Do not block the air intake. The audible tone going from a steady 1-2 clicks per second to an a solid alarm indicates a leak. Frequently adjust the balance knob in order to maintain the rate of 1-2 clicks per second.

Service Ports/Access Valves

The primary seal for the service ports is the sealing cap. This cap contains a specially designed O-ring seal or gasket that provides a leak-free seal. A loose or missing cap, or using the wrong cap, results in the loss of the refrigerant charge.

Evaporator Core

Finding leaks in the evaporator core is very difficult. In order to leak test the core, complete the following steps

1. Turn the blower fan to the HI position for 15 seconds or longer. Then, turn the blower fan to the OFF position.
2. Wait 10 minutes.
3. Remove the passenger compartment air filter. Refer to Passenger Compartment Air Filter Replacement .
4. Insert the probe of the leak detector as close to the evaporator as possible. A solid alarm indicates the discovery of a leak.
5. If possible, visually inspect the core face for evidence of refrigerant oil. Use a flashlight.

Compressor Block Fitting and Shaft Seal

Complete the following steps

1. Blow shop air behind and in front of the compressor clutch/puller for at least 15 seconds.
2. Wait 1-2 minutes.
3. Probe the area in front of the pulley. A solid alarm indicates the discovery of a leak.

Heating Insufficient

Heating Insufficient

Air Delivery Improper

If the Function Test or other diagnosis indicates improper air delivery or a failure in the shifting of modes when moving the mode rotary knob. Inspect the attachment of the affected control cable at the heater module.

1. Ensure that the mode control cable connects to the mode actuator.
2. Ensure that the cable sheath is retained.
3. Observe the action of the mode control cable.

If the cause of the condition is not discovered, disconnect the mode control cable at the mode valve.

Inspect the system for the following conditions

1. Improper mode valve travel and effort
2. Improper mode control cable travel at the heater module end while moving the mode rotary knob is moving.
3. If the mode control cable does not move, inspect for a broken mode control cable or control assembly part.
4. An unattached mode control cable end at the control assembly
5. A sharp kink in the mode control cable sheath that may cause severe binding.

Preparation

With the engine sufficiently cool, perform the following steps

1. Remove the radiator cap.
2. Start the engine.
3. Let the engine idle.
4. Set the heater controls to the following: The HTR mode, the full RED temperature. The HIGH blower speed.

When the coolant flow in the radiator is visible through the filler neck, install the radiator cap.

Temperature Check

Warm up the engine for about 20 minutes with the engine running. Drive the vehicle at 48 km/h (30 mph). Use an accurate thermometer in order to determine the temperature of the outside air and the temperature of the air discharged at the floor outlets. The minimum acceptable heater output temperatures at 4 different outside temperatures are represented in the table in specifications.

High or Low Temperature Control Effort

High or Low Temperature Control Effort

Odor Correction

The air conditioning (A/C) system may emit odors at startup in hot climates. Debris in the heater/evaporator case or growth of mold on the evaporator core may cause the odor. A service kit is available through GMSPO. A single application of this deodorizer, GM P/N 12377951, will remove the odor from the A/C system.

1. Clear all the debris from the plenum that draws air from the outside.
2. Disconnect the clutch coil. Disconnecting the coil will disable the A/C compressor clutch operation.
3. Turn the engine on in order to dry the evaporator core. Run the blower motor on high and on a recirculating mode, with a temperature control on maximum heat for 10 minutes.
4. Remove the passenger compartment air filters. Refer to «Passenger Compartment Air Filter Replacement»(ref-235301-S31553119302006061900000) .
5. Keep the blower motor on high. Insert the extension tube of the deodorizer, GM P/N 1237795, into the hole past the mark on the tube.
6. Spray the area with short bursts. Dispense the contents of the can over a 2-3 minute period. Vary the direction of the spray into the duct.
7. Turn the engine off.
8. Let the engine sit for 3-5 minutes.
9. Start the engine. Run the fan on high for 15-20 minutes in order to dry the area.
10. Reconnect the A/C compressor clutch coil. Verify the operation of the A/C system.

Refrigerant Recovery and Recharging

Tools Required

1. J 39500-B A/C Refrigerant Recovery, Recycling and Recharging (ACR4) System.
2. J 41810 Pureguard 2
3. J 41810-100A High Intensity Black Light. See «Special Tools»(ref-235300-S01064053572006061900000) .

Note. R-134a is the only approved refrigerant for use in this vehicle. The use of any other refrigerant may result in poor system performance or component failure.

Note. To avoid system damage use only R-134a dedicated tools when servicing the A/C system.

Note. Use only Polyalkylene Glycol Synthetic Refrigerant Oil (PAG) for internal circulation through the R-134a A/C system and only 525 viscosity mineral oil on fitting threads and O-rings. If lubricants other than those specified are used, compressor failure and/or fitting seizure may result.

Note. R-12 refrigerant and R-134a refrigerant must never be mixed, even in the smallest of amounts, as they are incompatible with each other. If the refrigerants are mixed, compressor failure is likely to occur. Refer to the manufacturer instructions included with the service equipment before servicing.

The J 39500-B removes the Refrigerant-134a from the vehicle's A/C system. See Special Tools . The recovery procedure uses one filtering cycle. The evacuation procedure uses an automatic multiple pass filtering cycle. These filtering cycles ensure a constant supply of clean, dry refrigerant for A/C system charging.

The Initial Set-Up Instruction Manual, provided with the J 39500-B , contains specific procedures for proper recovery, evacuation and recharging. See Special Tools .

For ACR4 technical assistance in the U.S., call 1-800-345-2233.

Compressor Oil Level Check

Up to 120 ml (4 fl oz) of oil can collect in the crankcase. When you replace a compressor, drain and measure the old compressor crankcase oil. Discard the oil after recording the amount.

All replacement compressors are shipped dry. Follow the instructions shipped with the dry replacement compressor.

Seal Leak Detection

Do not change a shaft seal because of small amounts of oil on an adjacent surface. Only replace a shaft seal after you find actual refrigerant leakage using an approved leak detector, such as J 39400 or equivalent. See Special Tools .

Tools Required

1. J 39500-B R-134a A/C Refrigerant Recovery, Recycling and Recharging System (ACR4). See «Special Tools»(ref-235300-S01064053572006061900000) .
2. J 5403 Snap Ring Pliers. See «Special Tools»(ref-235300-S01064053572006061900000) .
3. J 23128-A Seal Seat Remover and Installer. See «Special Tools»(ref-235300-S01064053572006061900000) .
4. J 9553-01 O-Ring Remover. See «Special Tools»(ref-235300-S01064053572006061900000) .

1. Recover the refrigerant using the J 39500-B . See «Special Tools»(ref-235300-S01064053572006061900000) .
2. Loosen and reposition the compressor in the mounting brackets, if necessary.
3. Remove the clutch plate and hub assembly from the compressor. Refer to «Compressor Clutch Plate and Hub Assembly Removal»(ref-235300-S32122715592006061900000) .
4. Remove the shaft seal retainer ring (1) using the J 5403 . See «Special Tools»(ref-235300-S01064053572006061900000) .
5. Any dirt or foreign material in the compressor may cause damage. Thoroughly clean the following components: The inside of the compressor neck area surrounding the shaft The exposed portion of the seal The retainer ring groove The shaft
6. Fully engage the knurled tangs of the J 23128-A into the recessed portion of the seal (1) by turning the handle clockwise. See «Special Tools»(ref-235300-S01064053572006061900000) .
7. Remove the seal (1) from the compressor using a rotary-pulling motion. Discard the seal.
8. Securely hand-tighten the handle. Do not use a wrench or pliers.
9. Remove and discard the seal seat O-ring (1) from the compressor neck using the J 9553-01 . See «Special Tools»(ref-235300-S01064053572006061900000) .
10. Inspect the shaft and the inside of the compressor neck for dirt or foreign material. Ensure that the shaft and the inside of the compressor neck are perfectly clean before installing the new parts.
11. Thoroughly clean the O-ring seal groove in the front head.

Clutch Rotor and/or Bearing Install

Tools Required

1. J 6083 Snap Ring Pliers. See «Special Tools»(ref-235300-S01064053572006061900000) .
2. J 33023-A Puller Pilot. See «Special Tools»(ref-235300-S01064053572006061900000) .
3. J 41552 Pulley Puller. See «Special Tools»(ref-235300-S01064053572006061900000) .
4. J 29886 Driver Handle. See «Special Tools»(ref-235300-S01064053572006061900000) .
5. J 21352-A Support Block. See «Special Tools»(ref-235300-S01064053572006061900000) .
6. J 9481-A Bearing Installer. See «Special Tools»(ref-235300-S01064053572006061900000) .
7. J 33019 Bearing Staking Tool. See «Special Tools»(ref-235300-S01064053572006061900000) .
8. J 33017 Pulley and Bearing Assembly Installer. See «Special Tools»(ref-235300-S01064053572006061900000) .
9. J 8433-1 Puller Bar. See «Special Tools»(ref-235300-S01064053572006061900000) .
10. J 9398-A Bearing Remover. See «Special Tools»(ref-235300-S01064053572006061900000) .
11. J 34992 Holding Fixture. See «Special Tools»(ref-235300-S01064053572006061900000) .

1. Place the pulley rotor on the J 21352-A in order to fully support the rotor hub during bearing installation. See «Special Tools»(ref-235300-S01064053572006061900000) .
2. Use the following tools in order to align the new bearing squarely with the hub bore. The J 41552 . The J 9481-A . The J 29886 . See «Special Tools»(ref-235300-S01064053572006061900000) .
3. Drive the bearing fully into the hub. The installer will apply force to the outer race of the bearing, if used as shown.
4. Place the J 33019 in the hub bore. See «Special Tools»(ref-235300-S01064053572006061900000) .
5. Shift the rotor and bearing assembly on the J 21352-A in order to fully support the hub under the staking pin location. See «Special Tools»(ref-235300-S01064053572006061900000) . Use a heavy-duty rubber band (1) in order to hold the stake pin in the guide. Properly position the stake pin in the guide after each impact on the pin.
6. Strike the staking pin with a hammer until a metal stake, similar to the original, forms down to but not touching the bearing.
7. Stake 3 locations on the bearing race 120 degrees apart as shown.
8. With the compressor mounted on the J 34992 , position the pulley rotor (1) and the bearing assembly on the front head. See «Special Tools»(ref-235300-S01064053572006061900000) .
9. Position the J 33017 and the J 33023-A directly over the inner race of the bearing. See «Special Tools»(ref-235300-S01064053572006061900000) .
10. Position the J 8433-1 on the J 33023-A . See «Special Tools»(ref-235300-S01064053572006061900000) .
11. Assemble the 2 through bolts and the washers through the puller bar slots.
12. Thread the through bolts into the J 34992 . See «Special Tools»(ref-235300-S01064053572006061900000) . Ensure that the thread of the through bolts engage the full thickness of the J 34992 . See «Special Tools»(ref-235300-S01064053572006061900000) .
13. Tighten the center screw in the J 8433-1 in order to force the pulley rotor and bearing assembly onto the compressor front head. See «Special Tools»(ref-235300-S01064053572006061900000) . If the J 33017 slips off direct in-line contact with the inner race of the bearing, perform the following steps:. See «Special Tools»(ref-235300-S01064053572006061900000) . Loosen the J 8433-3 . See «Special Tools»(ref-235300-S01064053572006061900000) . Realign the installer and the pilot in order to ensure that the J 33017 properly clears the front head. See «Special Tools»(ref-235300-S01064053572006061900000) .
14. Use the snap ring pliers in order to install the following components
15. The pulley rotor (1)
16. The retaining ring (2)
17. Install the clutch plate and hub assembly. Refer to «Compressor Clutch Plate and Hub Assembly Removal»(ref-235300-S32122715592006061900000) .

Compressor Clutch Coil Install (Harrison)

Tools Required

1. J 33024 Clutch Coil Installer Adapter. See «Special Tools»(ref-235300-S01064053572006061900000) .
2. J 8433-1 Puller Bar. See «Special Tools»(ref-235300-S01064053572006061900000) .
3. J 34992 Holding Fixture. See «Special Tools»(ref-235300-S01064053572006061900000) .
4. J 33017 Pulley and Bearing Assembly Installer. See «Special Tools»(ref-235300-S01064053572006061900000) .
5. J 33023-A Puller Pilot. See «Special Tools»(ref-235300-S01064053572006061900000) .
6. J 6083 Snap Ring Pliers. See «Special Tools»(ref-235300-S01064053572006061900000) .

1. Place the clutch coil assembly (1) on the front head. Position the terminals at the marked location.
2. Place the J 33024 over the internal opening of the clutch coil housing. See «Special Tools»(ref-235300-S01064053572006061900000) .
3. Align the J 33024 with the compressor front head. See «Special Tools»(ref-235300-S01064053572006061900000) .
4. Center the J 8433-1 in the counter-sunk center hole of the J 33024 . See «Special Tools»(ref-235300-S01064053572006061900000) .
5. Install the 2 through bolts and washers through the crossbar slots.
6. Thread the bolts into the J 34992 in order to achieve full fixture thickness. See «Special Tools»(ref-235300-S01064053572006061900000) .
7. Turn the center forcing screw of the J 8433-1 in order to force the clutch coil onto the front head. See «Special Tools»(ref-235300-S01064053572006061900000) . Ensure that the clutch coil and the J 33024 remain aligned during installation. See «Special Tools»(ref-235300-S01064053572006061900000) .
8. When the coil is fully seated on the front head, use a 1/8 inch diameter drift punch (2) in order to stake the front head at 3 places 120 degrees apart (3), in order to ensure that the clutch coil (1) remains in position.
9. Ensure that the stake size is only one-half the area of the punch tip. Ensure that the stake is only approximately 0.28-0.35 mm (0.010-0.015 in) deep.
10. With the compressor mounted to the J 34992 , position the pulley rotor (1) and bearing assembly on the front head. See «Special Tools»(ref-235300-S01064053572006061900000) .
11. Position the J 33017 and the J 33023-A directly over the inner race of the bearing. See «Special Tools»(ref-235300-S01064053572006061900000) .
12. Position the J 8433-1 on the J 33023-A . See «Special Tools»(ref-235300-S01064053572006061900000) .
13. Assemble the 2 through bolts and washers through the puller bar slots.
14. Thread the bolts into the J 34992 . See «Special Tools»(ref-235300-S01064053572006061900000) . Ensure that the thread of the through bolts engages the full thickness of the J 34992 . See «Special Tools»(ref-235300-S01064053572006061900000) .
15. Tighten the center screw in the J 8433-1 in order to force the pulley rotor and bearing assembly onto the compressor front head. See «Special Tools»(ref-235300-S01064053572006061900000) . If the J 33017 slips off direct in-line contact with the inner race and bearing, Perform the following steps:. See «Special Tools»(ref-235300-S01064053572006061900000) . Loosen the J 8433-3 . See «Special Tools»(ref-235300-S01064053572006061900000) . Realign the installer and the pilot in order to ensure that the J 33017 properly clears the front head. See «Special Tools»(ref-235300-S01064053572006061900000) .
16. Use the J 6083 in order to install the following components:. See «Special Tools»(ref-235300-S01064053572006061900000) . The pulley rotor (1) The retainer ring (2)
17. Install the clutch plate and hub assembly. Refer to «Compressor Clutch Plate and Hub Assembly Removal»(ref-235300-S32122715592006061900000) .

Compressor Clutch Coil Install (Denso)

1. Install the coil assembly to the compressor.
2. Install the coil snap ring.
3. Install the coil connector retaining bracket screw. Tighten: Tighten the screw to 9 N.m (80 lb in).
4. Install the clutch hub/bearing assembly.
5. Install the clutch hub/bearing snap ring.
6. Install the clutch plate assembly.
7. Install the clutch plate retaining bolt (1). Tighten: Tighten the bolt to 18 N.m (13 lb ft).

Compressor Shaft Seal Install

Tools Required

1. J 39500-B R-134a A/C Refrigerant Recovery, Recycling and Recharging System (ACR4). See «Special Tools»(ref-235300-S01064053572006061900000) .
2. J 5403 Snap Ring Pliers. See «Special Tools»(ref-235300-S01064053572006061900000) .
3. J 23128-A Seal Seat Remover and Installer. See «Special Tools»(ref-235300-S01064053572006061900000) .
4. J 33011 O-Ring Installer. See «Special Tools»(ref-235300-S01064053572006061900000) .
5. J 34614 Shaft Seal Protector. See «Special Tools»(ref-235300-S01064053572006061900000) .
6. J 39893 Pressure Testing Connector. See «Special Tools»(ref-235300-S01064053572006061900000) .

1. Dip the new seal seat O-ring in clean 525 viscosity refrigerant oil. Assemble the new seal seat O-ring onto the J 33011 . See «Special Tools»(ref-235300-S01064053572006061900000) .
2. Insert the J 33011 into the compressor neck until the installer bottoms. See «Special Tools»(ref-235300-S01064053572006061900000) .
3. Lower the moveable slide of the J 33011 in order to release the O-ring into the seal O-ring lower groove. See «Special Tools»(ref-235300-S01064053572006061900000) . Do not release the O-ring into the compressor neck top groove.
4. Rotate the J 33011 in order to seat the O-ring. See «Special Tools»(ref-235300-S01064053572006061900000) .
5. Remove the J 33011 . See «Special Tools»(ref-235300-S01064053572006061900000) .
6. Dip the new seal in clean 525 viscosity refrigerant oil. Assemble the seal to the J 23128-A by turning the handle clockwise.
7. Engage the knurled tangs of the J 23128-A with the stamped steel case side of the lip seal (1) in order to ensure that the flared-out side of the lip seal (1) faces toward the compressor. See «Special Tools»(ref-235300-S01064053572006061900000) .
8. Install the seal using 1 of the 2 following methods
9. When using method 1 do the following
10. Install the J 34614 in the seal lip. See «Special Tools»(ref-235300-S01064053572006061900000) . Place the seal lip over the compressor shaft. Push the seal (1) into place using a rotary motion.
11. When using method 2 do the following
12. Place the J 34614 over the end of the compressor shaft. See «Special Tools»(ref-235300-S01064053572006061900000) .
13. Slide the new seal (1) onto the shaft using a rotary motion until the seal stops. Ensure that the seal contacts the O-ring. Do not dislodge the O-ring. Disengage the installer from the seal. Remove the J 23128-A and the J 34614 . See «Special Tools»(ref-235300-S01064053572006061900000) .
14. Using the J 5403 , install the new seal retainer ring (1) with the flat side against the seal. See «Special Tools»(ref-235300-S01064053572006061900000) . Use the sleeve from J 33011 in order to press in the seal retainer in order to ensure that the seal snaps into the groove. See «Special Tools»(ref-235300-S01064053572006061900000) .
15. Perform a leak test using the following procedure: Install the J 39893 on the rear head of the compressor. See «Special Tools»(ref-235300-S01064053572006061900000) . Connect the gage charging lines and the J 39500-B . See «Special Tools»(ref-235300-S01064053572006061900000) . Pressurize the suction and the high-side of the compressor using R-134a Refrigerant. Temporarily install a M9 x 1.25 threaded nut on the shaft. With the compressor in a horizontal position, rotate the compressor shaft in the normal direction of rotation several turns by hand. Leak test the seal area. Correct any leaks found. Recover the refrigerant. Remove the shaft nut.
16. Remove any excess oil from the shaft and from the inside of the compressor neck.
17. Install the clutch plate and hub assembly. Refer to «Compressor Clutch Plate and Hub Assembly Removal»(ref-235300-S32122715592006061900000) .
18. Install the compressor belt. Tighten the bracket.
19. Evacuate and charge the refrigerant system.

Compressor Pressure Relief Valve Install

Tools Required

J 39500-B R-134a A/C Refrigerant Recovery, Recycling and Recharging System (ACR4). See Special Tools .

1. Clean the valve seat area on the rear head.
2. Lubricate the O-ring of the new pressure relief valve (5) and the O-ring assembly using new 525 viscosity refrigerant oil.
3. Install the new pressure relief valve (5). Tighten: Tighten the new valve to 9.0 N.m (6.1 lb ft).
4. Evacuate and recharge the system using the J 39500-B . See «Special Tools»(ref-235300-S01064053572006061900000) .
5. Leak test the system.

Tools Required

J 39400-A Halogen Leak Detector

J 43181 Quick Connect Connector Removal Tool. See Special Tools .

J 43181 Quick Connect Connector Removal Tool. See Special Tools .

J 39400-A Halogen Leak Detector

J 39400-A Halogen Leak Detector

J 39400 Leak Detector. See Special Tools .

Heater and Air Conditioning (A/C) Pipe Repair - Auxiliary

Do not service the rear heater lines as a complete unit. Service the rear heater lines as a sectional repair.

You can obtain the different sections of line through GMSPO.

J 41425 A/C Line Repair Kit. See Special Tools .

Use the J 41425 when any of the following actions damage the A/C or heater lines:. See Special Tools .

1. Rub-through
2. Collision damage
3. Leakage in the system

Follow the Straight Line Repair procedure in order to repair the type of damage described above.

If the A/C or heater lines have visible damage or a leak in a bend area, replace the lines. Section the lines in order to obtain the original line shapes. Maintaining the original line shape will prevent vibrations and rub-through.

Follow the A/C Line Sectioning Repair procedure in order to repair any damage in a bend area.

Straight Line Repair

1. If you are repairing the A/C lines, evacuate, charge and leak test the system. Refer to «Refrigerant Recovery and Recharging»(ref-235300-S36021813022006061900000) .
2. If you are repairing the heater lines, drain the cooling system.
3. Raise and support the vehicle.
4. Locate the area that requires repair.
5. Use a tubing cutter in order to cut the damaged line for repair.
6. Use the cleaning pad from the J 41425 in order to clean any burrs or grease. See «Special Tools»(ref-235300-S01064053572006061900000) . Be sure to clean at least 19 mm (0.75 in) from the A/C line.
7. Use the LOK prep sealant in order to prep the A/C line.
8. Apply one drop of the J 41425 -3 sealing compound to the outside of each end of the line. See «Special Tools»(ref-235300-S01064053572006061900000) .
9. Install the correct LOK fitting into the jaws: Insert the line ends into the LOK fitting. Rotate the LOK fitting one complete turn in order to evenly distribute the sealing compound around the lines.
10. Verify that the connector ends are positioned in the counter bores of the jaw.
11. Install the J 41425-1 tool over the connectors and the tubes.
12. Hold the tool body with a 3/8 breaker bar. Turn the forcing screw until both of the connector collars bottom on the center shoulder of the LOK fitting.
13. Loosen the forcing screw. Remove the tool from the repaired line.
14. Verify that the LOK fitting is correctly installed.
15. Lower the vehicle.
16. If you drained the cooling system, refill the coolant.
17. If you are repairing the A/C lines, recharge and leak test the system. Refer to «Refrigerant Recovery and Recharging»(ref-235300-S36021813022006061900000) .

A/C Line Sectioning Repair

1. If you are repairing the A/C lines, evacuate the system. Refer to «Refrigerant Recovery and Recharging»(ref-235300-S36021813022006061900000) .
2. If you are repairing the heater lines, drain the cooling system.
3. Raise and support the vehicle.
4. Obtain a new A/C line for sectioning.
5. Scribe a mark on the damaged A/C line that will be cut. Refer to the Minimum Tube Length Required table.
6. Scribe a mark on the new line that will be sectioned.
7. Use a tubing cutter in order to cut both of the A/C lines.
8. Use the cleaning pad from the J 41425 in order to clean any burrs or grease. See «Special Tools»(ref-235300-S01064053572006061900000) . Be sure to clean at least 19 mm (0.75 in) from the A/C line.
9. Use the LOK prep sealant in order to prep the A/C line.
10. Apply one drop of the J 41425-3 sealing compound to the outside of each line end.
11. Install the correct LOK fitting into the jaws: Insert the line ends into the LOK fitting. Rotate the LOK fitting one complete turn in order to evenly distribute the sealing compound around the lines.
12. Verify that the connector ends are positioned in the counter bores of the jaw.
13. Install the J 41425-1 tool over the connectors and the tubes.
14. Hold the tool body with a 3/8 breaker bar. Turn the forcing screw until both of the connector collars bottom on the center shoulder of the LOK fitting.
15. Loosen the forcing screw. Remove the tool from the repaired line.
16. Verify that the LOK fitting is correctly installed.
17. Repeat Steps 4-13 for the other end of the repair line.
18. Lower the vehicle.
19. If you drained the cooling system, refill the coolant.
20. If you are repairing the A/C lines, recharge and leak test the system. Refer to «Refrigerant Recovery and Recharging»(ref-235300-S36021813022006061900000) .

Minimum Tube Length Required

Auxiliary Heater

An optional auxiliary heater supplies heat to the vehicle. The unit operates independently of the standard heater. The control on the instrument panel regulates the unit. The system consists of a separate heater core and the blower fan.

The heater hoses extend from the unit to a vacuum operated water valve. The hoses connect to the standard heater hoses.

Blower Speed Control-Auxiliary

The 3-speed blower switch provides the following settings

1. LO
2. MED
3. HIGH

The blower motor switch is located in the instrument panel, above the radio. The blower motor switch also triggers an electro-mechanical valve to control coolant flow to the auxiliary heater core.

In the LO speed position, the circuit continues through the heater wiring harness to 2 resistors in the blower motor resistor relay.

In the MED speed position, the circuit continues through the heater wiring harness to 1 resistor in the blower motor resistor relay.

In the HIGH speed position, the circuit continues through the heater wiring harness to the blower motor resistor relay, and closes the relay's normally open contact. This provides full power to the blower motor from the HVAC MaxiFuse®.

The Temperature Valve and The Heater Core

The temperature of the air coming from the heater duct and the defroster nozzle is regulated by controlling the relative amounts of warm and cool air coming from the heater module. The temperature valve determines the amount of the total airflow that passes through the heater core.

When the temperature knob in the control assembly is at the extreme left side of travel, the full BLUE, or cold position, the temperature valve stops all the airflow through the heater core. The heater duct and the defroster nozzle receive only unheated air.

When the temperature knob moves away from the full BLUE, or cold position, the temperature valve opens to allow an increasing amount of air to pass through the heater core. At the same time, the temperature valve reduces the amount of unheated air that enters into the mixture. The result is a very responsive control of the temperature of the air discharged through the heater ducts and the defroster nozzle.

When the temperature knob reaches the full RED, or hot position, to the extreme right end of travel, the temperature valve diverts all the airflow through the heater core for maximum heating.

Hot coolant from the engine moves through the heater core and returns to the cooling system when the engine is running.

The Mode Valves

The heater system provides the following 5 basic operating modes

1. Upper Mode
2. Bi-Level Mode
3. Lower Mode
4. Defog Mode
5. Defrost Mode

Refrigerant R-134a

Refrigerant performs the following functions in the air conditioning system

1. Absorbs heat
2. Carries heat
3. Releases heat

These vehicles use Refrigerant-134a (R-134a). Refrigerant-134a is a nontoxic, nonflammable, clear, colorless liquefied gas.

Handling Refrigerant R-134a

Handling Compressor Oil

Use approved compressor oil from a closed, sealed container. When adding refrigerant oil, the transfer device and container should be clean and dry to minimize the possibility of contamination. Refrigerant oil is moisture-free and will readily absorb moisture from the air. Do not open the oil container until the service procedure requires oil. Cap the oil immediately after use. Always store compressor oil in a closed sealed container. Compressor oil left in open or improperly sealed containers will absorb moisture. Do not reuse oil that has been removed from the refrigeration system. Dispose of used oil properly, according to local regulations.

Handling of Refrigerant Lines and Fittings

1. Ensure that the metal lines do not exhibit the following conditions. This will prevent the loss of system capacity due to line restriction: Dents Kinks
2. Do not bend the flexible hose line to a radius of more than 4 times the diameter of the hose.
3. Do not allow the flexible hose line to come within a distance of 63.5 mm (2 1/2 in) of the exhaust manifold.
4. Inspect the flexible hose lines regularly. Replace the flexible hose line with new hose if one of the following conditions exist: Leaks Brittleness Deterioration
5. Before disconnecting any fitting in the refrigeration system, discharge all of the Refrigerant-134a. Refer to Refrigerant Recovery and Recharging .
6. Once you open a refrigerant line to the atmosphere, cap or tape the line immediately. This will prevent any of the following items from entering the line: Moisture Dirt
7. Use the proper wrenches when you make connections on the O-ring fittings. Back-up the opposing fitting with a wrench in order to prevent distortion of the following areas: The connecting lines The components
8. Tighten all of the tubing connections to the specified torque. Too much or too little torque may result in the following conditions: Loose joints Deformed joint parts Refrigerant leakage An inoperative A/C system
9. Ensure that the O-rings and the seats are in perfect condition. A burr or a piece of dirt may cause a refrigerant leak.
10. Install new O-rings that you have lubricated with the mineral base 525 viscosity refrigerant oil. Do not use polyalkylene glycol (PAG) synthetic oil. Do not wipe the threads with a cloth.
11. Keep PAG synthetic refrigerant oil off fitting threads. Long term contact of PAG synthetic oil on threads may cause future disassembly difficulties. Flush threads of fitting with mineral base 525 viscosity refrigerant oil. Do not use PAG synthetic oil. Do not wipe threads with a cloth.

Handling Air Conditioning (A/C) Compressor

Do not strike, drop, or turn the compressor upside down. If the compressor is knocked over or turned upside down, rotate the compressor's clutch 5-6 times by hand to circulate the oil which has settled in the cylinder. Sudden rotation with oil in the cylinder can cause valve damage and adversely affect durability.

Maintaining Chemical Stability

The chemical stability of the refrigeration system plays an important role in the efficient operation and longevity of the A/C system.

When air, moisture or particulate contamination are introduced into the refrigeration system, the following results will occur

1. The chemical stability of R-134a and polyalkylene glycol (PAG) synthetic lubricant will change.
2. The pressure/temperature symmetry will change.
3. The A/C system efficiency will be diminished.
4. Internal A/C system parts may corrode and/or wear in an abnormal manner.

Use the following general practices to maintain chemical stability in the refrigeration system

1. Wipe away dirt and/or oil before you break a refrigerant connection. This will reduce the possibility of particulate contamination.
2. Cap, plug or tape both sides of an open connection as soon as possible. This will minimize the amount of dirt and moisture entering the system.
3. Ensure that the following remain clean and dry: The tools being used for the repair The surrounding area of the repair The hoses and connectors for the ACR4 machine or manifold gage set The replacement parts
4. When adding polyalkylene glycol (PAG) lubricant, ensure the transfer device and the container remain clean and dry to minimize moisture intrusion.
5. Do not leave the A/C system open any longer than necessary.
6. Before recharging an A/C system that has been opened, properly evacuate and vacuum test the system.
7. Service parts are dehydrated and sealed prior to shipping. Retain the parts in their sealed packages until you are ready to use them.
8. Ensure the parts are at room temperature before opening the packages. This prevents condensation on the parts from humidity in the atmosphere.
9. Attach the A/C service equipment quick-connects as soon as possible after removing the service caps.

Upper Mode

With the mode knob in the Upper position, the vent valve opens so air can flow to the instrument panel outlet ducts.

Lower Mode

When the mode knob is in the Lower position, the vent valve partially closes. The defroster valve remains closed. The blower fan heats the air and directs the heated air to the defroster valve. The defroster valve sends most of the airflow to the heater duct and some to the defroster nozzle.

Bi-Level Mode

When the mode knob moves to the Bi-Level position, the defroster valve moves to uncover more of the opening to the defroster. An increasing amount of air flows to the defroster nozzle, and a decreasing amount of air flows to the heater duct.

Defrost Mode

When the mode knob is in the Defrost position, the defroster valve moves to fully uncover the opening to the defroster nozzle and restrict the opening to the heater duct. The defroster nozzle receives the maximum airflow, with only a little amount of airflow coming from the heater duct.