1973 OPEL GT-R service

98.94 1973 OPEL SERVICE MANUAL
7. Remove 2 upper evaporator attaching nuts. See
Figures 9B-178 and 9B-181.
Figure 98-181 Location of Upper Evaporator
Attaching Bolt (Right Side)
8. Remove 2 attaching case mpunting bracket to
instrument panel screws. See Figure 9B-182.
Figure SB-182 Evaporator and Blower AssemblyBrackets and Attachments9. From underneath evaporator case, disconnect
two (2) drain hoses.lo. Carefully
PXIIOVS assembly from car. See Figure
9B-184.
11. Disconnect resistor electrical connector and
remove resistor assembly. See Figure
9B-184.12. Remove the blower case and blower motor at-
taching screws and remove assembly. See Figure 9B-
184.Installation
1. Install the blower motor assembly into caseFigure 98-183 Drain Hose
BLOWER MOTOR
Figcre 98.184 Assembly Removed
bracket with the electrical connector side of the mo-
tor to the right side ofthe bracket. Attach the mount-
ing strap.
2. Assemble the case halves and attach the cover
plate.
3. Install the resistor assembly and electrical con-
nector. Install blower motor connector. See Figure
9B-184.4. Install assembly into car carefully guiding
evaporator pipes up through cowl opening. See Fig-
ure 9B-185.
5. Install 2 upper evaporator attaching nuts. See
Figures 9B-178 and 9B-181.
6. Install 2 attaching case mounting bracket to in-
strument panel screws. See Figure 9B-182.

98.96 1973 OPEL SERVICE MANUALr DARK BLUE
LIGHT BLUE STRIPE
CUTOUT111111DARK GREEN DARK GREEN
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BATTERYl LJ
\flu- +tL-2+- -7- -RESISTOR
A
EXlSilNG‘IWIRE
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IFUSE BLOCK*,*,- I./SWITCH
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ti‘WIREfIfI
1- IAAI
i$+.-lAC~,‘XESW WIRE
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TTEVAPO.RATOREVAPO.RATOR
BLACK WITH RED STRIPE BLACK WITH RED
Sl96-143
Figure 9B-188 Wiring Schematic‘RIPE96-143
Figure 9B-188 Wiring Schematic
SPECIFICATIONS
Blower Motor Type
......................................................................................................12 VDC
Blower Fan Type
..................................................................................................Squirrel Cage

98.98 1973 OPEL SERVICE MANUALDIAGNOSISTROUBLE DIAGNOSIS GUIDE
Insufficient Cooling
CHECK AIR FLOW
FAN DOES NOT RUN
- Correct electrical fault.
FAN RUNS
- Check air velocity.
NOT OK
- Clean evaporator inlets.
Clean evaporator core.
Clean evaporator outlets.
OK
- Check refrigeration (refer to Refrigeration
Diagnosis Guide).
MAINTENANCE AND ADJUSTMENTS
ADJUSTMENT OF THERMOSTATIC SWITCHThe system makes use of a thermostatic switch with
a self-supporting air sensing capillary. This capillary
controls the switch by sensing the temperature of the
air leaving the evaporator tins.
Checking for Proper Operation
1. Install the gauge set, and set up the vehicle as
described under FUNCTIONAL TESTING SYS-
TEM in Refrigerant Components Section.
2. Movement of the temperature control knob
should result in a definite change in suction pressure
and cycling of the compressor clutch.
3. If compressor continues to operate regardless of
the knob adjustment it indicates that the switch
points are fused, which will lead to evaporator
freeze-up. The switch should be replaced.
Adjusting Switch
If after the foregoing checks, the switch seems to be
operating correctly, adjust for proper setting if neces-
sary, as follows:
1. Set up car as described in FUNCTIONAL
TESTING SYSTEM in Refrigerant Components
Section.
2. The suction side of the system, read on the lowpressure gauge, should pull down to the pressure
shown in the chart in SPECIFICATIONS in Refrig-
erant Components Section.
3. Remove the duct assembly mtaining screws and
remove the duct assembly noting the position of the
air sensing capillary so that it can be reinstalled in
the same location as when removed. See Figure 9B-
190.Figure 98.190 Duct Assembly and Retaining Screws
Figure 9B-13 1 Duct Assembly
4. Remove the thermostatic switch retaining screws
and remove switch. Remove the non-metal end plate
from the switch to gain access to the switch adjusting
screw. Check the screw for stripped or otherwise
damaged threads.

gB-100 1973 OPEL SERVICE MANUAL
2. Remove the retaining screws from the duct as-
sembly. See Figure 9B-190.3. Lift up duct assembly and note the position of the
air sensing capillary so that it can be reinstalled in
the same location as when removed.
4. Remove the temperature control switch retaining
screws and remove switch.
Installation
1. Install the temperature control switch and secure
with the retainer screws.
2. Position the air sensing capillary in the exact
location as was noted when removing.
3. Install the duct assembly retaining screws.
4. Install the negative battery cable.
REMOVAL AND INSTALLATION OF RESISTOR
ASSEMBLY
Removal1. Remove the negative battery cable from the bat-
tery.2. Remove the luggage tray attaching screws and
lift out tray. See Figure 9B-194.
Figure 98-194 Luggage Tray3. Remove all evaporator cover attaching screws
and remove cover. See Figure
9B’-195.Figure 98.195 Evaporator Cover Assembly and
Attaching Screws
4. Remove the electrical plug connector from the
resistor assembly.
5. Remove 2 resistor attaching screws and remove
resistor assembly. See Figure 9B-197.
/98-147Figure 9B-196 Resistor and Blower Motor
Connections

98-102 1973 OPEL SERVICE MANUAL
2. Discharge system. Refer to DISCHARGING
SYSTEM in Refrigerant Components Section.
3. While system is discharging remove the luggage
tray attaching screws and lift out tray. See Figure9B-200.
4. Remove all evaporator cover screws and remove
cover. See Figure
9B-201.Figure
98.202 Evaporator Cover and Luggage Tray5. Remove the electrical plug connector from the
resistor assembly, and unplug blower motor connec-
tion and remove ground wire. See Figure
9B-203.6. From underneath evaporator housing, discon-
nect 2 drain hoses. See Figure 9B-204.
EVAPORATORFigure
98.204 Drain Hose
7. From under car remove 4 nuts securing evapora-
tor mounting bracket to floor. See Figure 9B- 205
and 9B-206.
Figure
98.203 Electrical Connections and Ground
WireFigure 98-205 Evaporator Mounting Bracket Bolts -Driver Side

98-104 1973 OPEL SERVICE MANUAL
the el&trical connector side of the motor to the right
side of the bracket.
2. Assemble the fan housing case halves and attach
the cover plate.
3. Install the resistor assembly.
4. Install the evaporator assembly into the car and
install mounting bracket. See Figure
9B-209.5. Untape the refrigerant lines and the inlet and
outlet pipes from the evaporator and install using
new o-rings on line fittings.
6. From under the car, install 4 nuts securing
evaporator mounting bracket to floor. See Figures9B- 205 and
9B-206.7. Evacuate system. Refer to EVACUATING SYS-
TEM in REFRIGERANT COMPONENTS Sec-
tion.
SPECIFICATIONS8. While system is being evacuated:
9. Connect 2 drain hoses underneath the evaporator
housing.
10. Plug in the resistor assembly electrical connector
plug and connect the blower motor connection and
install ground wire and 2 mounting bracket to case
screws using the rearward holes.
S’ee Figure 9B-209.11. Install the evaporator cover and all cover screws.
See Figure 9B-202.
12. Install luggage tray and attaching screws. See
Figure
9B-202.13. Connect the negative battery cable.
14. Charge system. Refer to CHARGING SYSTEM
in Refrigerant Components Section.

RADIO. GT9c- 105
RADIO
GTCONTENTS
Subject
DESCRIPTION AND OPERATION: (Not Applicable)
DIAGNOSIS:
RadioTroubleDiagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MAINTENANCE AND ADJUSTMENTS:
Antenna Trimmer Adjustment
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MAJOR REPAIR:
RemovingandInstallingRadio. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SPECIFICATIONS: (Not Applicable)
Page No.
9c-105
9C-106
9c-107
DIAGNOSIS
RADIO TROUBLE DIAGNOSISBecause radio problems are most often repaired at
United Delco authorized warranty repair stations,
the tendency for many dealer servicemen is to
remove the set when a problem is reported, without
any preliminary diagnosis. This results in a large
number of radios showing up as “NO TROUBLE
FOUND” units when received by the warranty re-
pair stations. This indicates that the trouble can
often be corrected without removal of the radio.
The inconvenience to an owner of driving without a
radio while his set is being serviced at a warranty
station can frequently be avoided if the following
quick checks are used to eliminate external radio
system :problems before removing the radio for re-
pair.
Always determine from the owner the exact nature
of the radio problem as an aid to diagnosis. Knowing
whether the condition is intermittent or constant,
whether it occurs with engine off or running, with
car stationary or moving, will help to pinpoint the
problem. Never turn on radio with speaker discon-
nected.
Radio Ii
Inoperative.1. Turn on the radio. The dial should light and a
thump should be heard from the speaker.a. If a thump is heard, go to Step No. 2 for antenna
check.b. If no thump is heard,
check the fuse.
(1) If fuse is bad, replace and try radio again. Race
engine and, if fuse blows again,‘remove the radio and
speaker assembly for repair by
4 trained radio techni-
cian.
(2) If fuse is good, check to
s&e that the speaker-to-
receiver interconnecting cable is connected securely.
If there is still no thump when the radio is turned on,
remove the receiver and speaker for repair.
2. Check the antenna by substituting with one held
out the car window.
a. If radio is still dead with substitute antenna,
remove the receiver and spea!er for repair.
b. If radio operates near normal with substitute an-
tenna, some part of the car antenna or lead-in is at
fault.
Radio Reception Is Weak1. Check to see if antenna trimmer is peaked.
a. Position antenna at a height of 31 inches.
b. Tune radio to weak station at or near 1400 KHz
on the dial, and turn volume control to maximum.

9C-106 1973 OPEL SERVICE MANUAL
c. Adjust trimmer screw for maximum volume.
d. If antenna trimmer does not have a definite peak, check for defective antenna by substitution.
2. Check that the speaker connection is plugged in
SXUdY.
3. If the radio is still weak, remove the receiver and
speaker assembly for repair.
Radio Is Noisy
1. Radio is noisy all the time:
a. Check for defective antenna by striking antenna
with hand. If static is heard while tapping, replace
antenna.
b. If antenna is not defective, remove receiver and
speaker for repair.
2. Radio is noisy only when jarred:
a. Check antenna as in Step No. 1 above.
b. Check speaker connection. If speaker connection is not at fault, remove receiver and speaker for re-
pair.
3. Radio is noisy when engine is running:
a. Check noise suppressor by substituting on genera-
tor with known good one.
b. Check to see that antenna is mounted securely,
grounding the antenna base to the fender. The an-
tenna lead-in wire is shielded and the shield should
have good ground connection at the receiver and the
antenna base.
c. Check for other car wiring, passing too close to
radio receiver case.
d. If engine noise is still present, remove receiver and
speaker for repair.
4. Radio is noisy when car equipment is operated,
such as directional lights or brake lights:
Check for defective antenna lead-in wire or, loose
antenna mounting, as in Step No. 3b above.
MAINTENANCE AND ADJUSTMENTS
ANTENNA TRIMMER ADJUSTMENT
An antenna trimmer adjusment screw is provided for
matching of the antenna coil in the receiver to the car antenna. This adjustment must always be made after
installation of a receiver or an antenna, or after re-
pair to these units. This adjustment should also be
performed whenever radio reception is unsatisfac-
tory.
1. Position antenna to a height of 31 inches.
2. Tune receiver
tb a weak station at or near 1400
KHz that can barely be heard
with volume turned
fully up.
3. Insert a small-bladed screwdriver in antenna trim-
Figure 9C-1 Location of Access Trim Plug
Figure
9C-2 Removing Hex Head Screw