A/C - Insufficient Cooling/Code F48 Set

91caddy02
Bulletin No. T-91-52
File in Group 1
Number 73
Corp. Ref. No. 011203
Date Feb. 1991




SUBJECT: INSUFFICIENT COOLING IN A/C MODE AND/OR CODE F48 AND/OR PRESSURE RELIEF VALVE BLOW OFF


MODELS AFFECTED: 1991 DE VILLES AND FLEETWOODS


Some 1991 DeVilles and Fleetwoods with VIN breakpoints prior to M4217597 may experience insufficient cooling, code 48 for low pressure switch open, or pressure relief valve blow off due to dislocation of the orifice tube.

To diagnose this condition:
A. Recover refrigerant from A/C system.

B. Separate tube assembly as shown in Figure 2, Item 3.

Figure 1 - Placement of Orifice:

C. Inspect placement of orifice as shown in Figure 1.


If the orifice tube is properly located, refer to the Climate Control System Check in Section 1C of the Service Information Manual. If the orifice tube is not located properly, use the following procedure:

Figure 2 - A/C Refrigerant Lines:

1. Remove evaporator tube (Figure 2, Items 2 and 6) assembly from evaporator inlet pipe and at condenser.


2. Remove complete assembly and replace with P/N 25553643 which includes the orifice tube.


NOTE: Coat O-rings with clean 525 viscosity refrigerant oil and hand start fittings to prevent O-ring damage and to secure a proper seal.


3. Torque to 24 N.m (18 lbs.ft.).


4. Be sure to fasten all A/C line clips to prevent grounding or distortion of tube. Refer to Figure 2, Views A, B, and C.


5. Evacuate, charge, and leak test A/C system.


Parts are currently available from GMSPO.

For warranty purposes use Labor Operation T6526 at 1.4 hours.