GMC 4000 Series Service Manual page 101

Sec. 1
Page 94
AIR CONDITIONING
BL O W E R M O T O R
W IR IN G C O N N E C T IO N
Figure 16 — Blower Motor W iring Connection
shut-off valve to force refrigerant through the unit.
The unit should be supported so that the refriger­
ant passing through it will be directed into an area
where -21.7 F., will do no damage.
CAUTION: Remember that when
liquid refrigerant is released from the
drum into an area where atmospheric
pressure exists, its temperature will
immediately drop to -21.7°F._________
In order to keep the expansion valve open when
flushing the evaporator, the expansion valve bulb
must be detached from the evaporator outlet tube.
G M C S E R V I C E M A N U A L
INSPECTING COMPRESSOR
tate com pressor shaft to test for normal reaction.
A quick check for broken reed valves is to turn
com pressor shaft (using box end wrench on com­
pressor shaft nut) and check for resistance when
turning the shaft. An irregular resistance force
will be felt as each of the pistons goes over top
center for each revolution of the crankshaft. If this
pattern is not felt, it indicates one or mere broken
com pressor reed valves and the com pressor must
be repaired.
indicate internal damage to the com pressor. If no
foreign matter is found in oil, com pressor can be
used. Flush entire refrigeration system with re­
frigerant, drain oil from com pressor and pour in
11 oz. of new Frigidaire 525 viscosity oil.
panel flange.
terminal (fig. 16).
pull back the cellular insulating material at motor
hose plate. Remove screws, then pull motor a s­
sembly from shroud. Rotate hose plate so that cut­
off is at the top before removing.
previous procedures.
down the insulating material using a light coat of
rubber cement.
If there is no visible evidence of damage, ro­
Inspect oil for foreign material which would
BLOWER MOTOR REPLACEMENT
1. Disconnect motor ground wire from dash
2. Pull motor switch lead at quick-disconnect
3. For access to blower mounting screw s,
4. Install the motor unit by reversing the
NOTE: After installing attaching screw s, seal