GMC 1982 Light Duty Truck Service Manual page 34

3. Place a clean pan under the vehicle and then disconnect
the h eater core inlet and outlet hoses at the core
connections (see " H e a te r Hoses-Replacement" later in
this section). Quickly plug the heater hoses and support
them in a raised position. Allow the coolant in the
heater core to drain into the pan on the floor.
4. Remove h eater distribu to r duct to distrib utor case
attaching screws and distributor duct to engine cover
screw and remove duct.
5. Remove engine housing cover.
6. Remove instrument panel attaching screws: above, at
windshield, all lower screws and right lower I.P.
support bracket at door pillar and engine housing.
7. Lower steering column, and raise and support right side
of I.P.
8. Remove defroster duct to distributor case attaching
screw, and 2 screws attaching distributor to heater
case.
9. Disconnect temperature door cable and fold cable back
for access (Refer to Fig. 1 A - 17).
10. Remove three (3) nuts at engine compartment side of
distributor case and one (1) screw on passenger side.
11. Remove the heater case and core as an assembly. Tilt
the case assembly rearward at the top while lifting up
until the core tubes clear the dash openings.
12. Remove the core retaining strap screws and remove the
core.
13. To install a new core, reverse Steps 1-10 above. Be sure
core to case and case to dash panel sealer is intact
before assembling unit.
HEATER HOSES
H eater hoses are routed from the thermostat housing
or inlet manifold and w ater pum p (ra d ia to r on some
autom atic transmission vehicles) to the core inlet and outlet
pipes as shown in Figures 1A-8 thru 1A-11. Hoses are
attached at each end with screw type clamps.
Fig. lA -7-H ea ter Distributor - G Models
R eplacem ent
The heater core can be easily damaged in the area of
the core tube attachm ent seams whenever undue force is
exerted on them. Whenever the heater core hoses do not
readily come off the tubes, the hoses should be cut just
forward of the core tubes. The portion of the hose remaining
on the core tube should then be split longitudinally. Once
the hoses have been split, they can be removed from the
tubes without damaging to the core.
DISTRIBUTOR DUCTS - G Models
R eplacem ent (Fig. 1A -12)
1. Disconnect the battery ground cable.
2. Raise I.P. at right side as outlined under heater
distributor removal.
3. Unsnap the engine cover front latches. Remove the two
cover to floorpan screws and remove the cover.
4. Remove the heater distributor duct to case attaching
screws as shown in Fig. 1 A - 12.
5. Remove one (1) screw at left center of distributor duct.
6. Pull the center distributor duct to the right and remove
it from the vehicle.
7. To install, reverse Steps 1 thru 5. Check cable and door
operation; cables should be free from kinks or binding
and doors should close properly. If cable adjustment is
necessary, refer to " Bowden C ab le-A djustm ent."
DEFROSTER DUCT
Defroster assemblies attachm ent are shown in Fig. 1A-
13.
CONTROL ASSEMBLY
C-K M odels
R eplacem ent (Fig. 1A -14)
1. Disconnect the battery ground cable.
2. Remove the instrument panel bezel.
3. Disconnect the bowden cables and the blower switch
HEATER 1A-9