Evaporator Core Replacement; Blower Motor Switch Replacement; Fuse Replacement - GMC G Service Manual

8. Valve inlet and outlet lines (341).
• Cap or plug open lines.
9. Expansion valve assembly (342).
R Install or Connect (Figures 55 and 56)
1. New expansion valve assembly (342).
• Remove caps or plug.
• Use new seals (O-rings) (340) coated with
clean refrigerant oil.
• Attach the sensing bulb and sensing bulb
clamps (347).
2. Lower case (336) and blower motor assembly (330).
3. Lower case-to-upper case screws (334)
4. Blower motor harness connector (332).
5. Ground wires (331).
6. Rear duct (303).
7. Battery ground cable.
• Evacuate, charge and check the system.
EVAPORATOR CORE
REPLACEMENT
H Remove or Disconnect (Figures 55 and 56)
1. Battery ground cable.
• Purge the system of refrigerant.
2. Rear duct (303).
3. Blower motor harness connector (332).
4. Ground wire (331).
5. Refrigerant lines at the rear of the blower-evaporator
assembly (351).
• Cap or plug the open connections.
6. Blower-evaporator support-to-roof rail screws (320
and 325).
7. Blower and evaporator core (339).
• Place the blower-evaporator upside down on a
work bench.
8. Lower case assembly (336).
9. Upper case (326) and supports (324) from the evapo­
rator core.
10. Expansion valve inlet and outlet lines (341).
• Cap or plug open connections.
11. Expansion valve sensing bulb from the evaporator
outlet line.
12. Valve (342).
13. Plastic pins (345) that hold the screen (346) to the
core.
14. Screen (346).
I4 * ! Install or Connect (Figures 55 and 56)
1. Wire screen (346) to the front of the core.
2. Plastic pins (345).
3. Expansion valve inlet and outlet lines (341).
• Use new seals (O-rings) (340) coated with
clean refrigeration oil.
4. Sensing bulb to the evaporator outlet line.
• Bulb must make good contact with the line.
AIR CONDITIONING IB-51
• Add 88.7 ml (3 ounces) of clean refrigerant oil to
new core.
5. Upper case (326) and supports (324) to the core.
6. Lower core case (336) and blower assembly.
7. Blower-evaporator assembly to the roof.
8. Support-to-roof rail screws (320 and 325).
9. Refrigerant lines (351) to the rear of the blower-evap­
orator unit.
• Use new seals (O-rings) (4) coated with clean
refrigeration oil.
10. Blower lead harness connector (332).
11. Ground wire (331).
12. Rear duct (303).
13. Battery ground cable.
• Evacuate, charge and check the system.
BLOWER MOTOR SWITCH
REPLACEMENT
The auxiliary heater and air conditioning blower switches
are located to the right of the steering wheel.
M Remove or Disconnect (Figure
1. Battery ground cable.
2. Switch retaining screws (280).
3. Wiring harness.
4. Switch (348) from bezel (282).
h H Install or Connect (Figure
1. Switch (348) into bezel (282).
2. Wiring harness.
3. Switch retaining screws (280).
Figure Blower Switch Replacement
57 —

FUSE REPLACEMENT

A 25-amp fuse at the fuse box protects this system. A
20-amp fuse, located between the junction block and the
rear blower motor switch, protects the rear blower high
speed circuit.
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