T Herm Ostatic Switch; Discharge Pressure S W Itch - Chevrolet 1977 light duty truck Service Manual

3. To install, reverse Steps 1 and 2 above.
BLOWER M O T O R RESISTO R
The blower motor resistor is located in the blower
side of the blower-evaporator case (fig. IB-43).
Replacement
1. Disconnect the wiring harness at the resistor.
2. Remove the resistor to case attaching screws and
remove the resistor.
3. Place the new resistor in position and install the
attaching screws.
4. Connect the resistor wiring harness.
BLOW ER M O TO R RELAY
T he blower motor relay is located on the blower side
o f the blower-evaporator case.
Replacement
1. Disconnect the wiring harness at the relay.
2. Remove the relay to case attaching screws and
remove the relay.
3. Place the new relay in position and drive the
m o unting screws.
4. Connect the relay wiring harness.
T H E R M O S T A T IC S W ITC H
The thermostatic switch is mounted on the bracket
which supports the inlet
e v ap orator case. The switch sensing capillary is attached
by means o f a clamp to the evap orato r inlet tube.
Removal
Fig. IB -4 3 -R e sisto r, Relay and T herm ostatic Switch
(C-K Models)
tube in position at the
1. Remove electrical connectors to the switch.
2. Remove screws to loosen body from evaporator
case.
3. A capillary line (small tube) extends from the
swtich with the other end attached to the evaporator inlet
pipe ( 1 /2 " O.D.) with two clamps. This end is covered
with an insulation material.
insulation and loosen clamps enough to pull the formed
end o f the capillary tube out from under the clamps.
Solvent clean pipe area to remove rem aining insulation
material and dirt.
4. Identify area by m arking the capillary tube
location on the inlet pipe from where it was removed.
The replacement switch's tube should be installed at this
location.
Installation
1. M ount switch body to previous location. Do not
over-torque screws. The recom mended reassembly torque
is 15-20 in. lbs. Do not dam age or distort the switch
body, as this m ay affect switch calibration.
2. M ount form ed end o f capillary tube to the inlet
pipe in SAME POSITION AS THE O R IG IN A L tube.
D O N O T INSTALL N E W TUBE M O R E T H A N 1/2" in
either direction o f previously marked location.
3. Adjust each clamp before tightening so that
width of the clamp covers the capillary tub e's formed
end. Tighten to 1.69 to 2.25 N m (15 to 20 in. lbs.) of
torque. Do not overtorque.
4. Re-cover tube and pipe with insulation material.
If original insulation is damaged, replace with same type
material. (G M P D Part No. 3014431 or equivalent).
5. Reconnect electrical terminals.

DISCHARGE PRESSURE S W ITCH

The discharge pressure switch is located in the
condenser to evaporator line (fig. IB-44).
Replacement
1. Disconnect the battery ground cable.
Carefully remove the