Rear A/C Unit - Blows Warm Air When Hot Outside: Overview
NUMBER: 24-05-99GROUP: Heater & A/C
DATE: Feb. 19, 1999
SUBJECT:
Rear A/C Unit Blows Warm Air When Ambient Temperatures Are High
OVERVIEW:
This bulletin involves installing front and rear expansion valves and in some cases, lowering the headliner and installing front and side/bottom seals to the rear A/C unit.
MODELS:
1998 - 1999 (DN) Durango
NOTE:
THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH REAR A/C (SALES CODE HBA) BUILT BEFORE DECEMBER 14, 1998 (MDH 1214XX).
SYMPTOM/CONDITION:
The rear A/C unit blows warm air out of the overhead ducts when ambient temperatures are greater than 32°C. (90°F.) with the rear A/C ON and with the front A/C functioning normally.
NOTE:
THE CONDITION MAY BE WORSE WITH HIGH SUN LOADS APPLIED TO THE ROOF PANEL OF THE VEHICLE.
DIAGNOSIS:
NOTE:
IF THE VEHICLE WAS BUILT BETWEEN OCTOBER 1, 1998 (MDH 1001XX) AND DECEMBER 14, 1998 (MDH 1214XX), PROCEED TO THE EXPANSION THERMAL VALVE REPAIR PROCEDURE.
1. Measure the ambient air temperature of the repair area. DO NOT proceed unless the ambient temperature is at least 21°C (70°F).
2. Connect a tachometer.
3. Set the heater-A/C mode control switch knob to the MAX A/C position. Set the temperature control knob to the full cool position. Set the blower motor switch knob of both the front A/C and rear overhead A/C systems to the high speed position.
4. Start the engine and hold the engine speed at 1,000 rpm with the compressor clutch engaged. Operate the engine until the engine temperature reaches its normal operating range.
5. Position a thermometer inside the center inlet of the rear overhead A/C system approximately 19 mm (3/4 in.) ahead of the evaporator and measure the temperature of the air entering the evaporator (Figure 1).
NOTE:
DO NOT ALLOW THE TEMPERATURE PROBE TO CONTACT THE EVAPORATOR.
6. Position a thermometer approximately 19 mm (3/4 in.) in front of the center in let of the rear overhead A/C system and measure the temperature of the air coming into the rear A/C system through the center inlet (Figure 2).
7. If the temperature of the air directly ahead of the evaporator in the rear overhead A/C system is 20°C. (40°F.) greater than the air in front of the rear overhead A/C system's center inlet, perform the Expansion Thermal Valve Repair Procedure and the Rear A/C Evaporator Seal Repair Procedure.
PARTS REQUIRED:
1 55056017AA Seal, Rear A/C Front Foam
1 55056018AA Seal, Rear A/C Side/Bottom Foam
AR (1) 55055773AF Valve, Front Thermal Expansion
AR (1) 55055876AB Valve, Rear Thermal Expansion
AR (1) 55055728AD Label, Refrigerant Charge
AR 04886129AA Oil, SP-20 PAG Refrigerant
AR 82300101 Refrigerant, R134-A
AR (1) 05015797AA Clip, Electronic Cycling Clutch Switch
POLICY: Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
Labor Operation No:
24-65-24-90 Install Rear Overhead A/C Housing Seals 0.9 Hrs.
24-35-20-91 Remove And Install Front And Rear Expansion Valves
(Includes Recover And Recharge The A/C System) 0.8 Hrs.
FAILURE CODE: P8 - New Part