HEATER AND AIR CONDITIONING 1A-54
Fig.
71-Wiring-AH Weather (Chevy II)
1.
Loosen the lock screws and remove the two control
knobs from the front of the evaporator unit. Then
use a suitable spanner wrench to remove the two
nuts beneath the control knobs.
2.
Remove the screws (located in the outer ball outlets)
attaching the face plate.to the evaporator case. Then
remove the face plate and, reaching through this
opening, carefully remove the plug attaching the
thermostatic switch capillary tube to the evaporator
core.
3.
Turning the unit over, remove the screws attaching
the back cover and gasket to the case and remove
the cover and gasket.
4.
From the top of the case, remove the screws attach-
ing the evaporator core brackets to the case.
5.
Carefully draw the core and expansion valve assem-
bly out of the case.
NOTE: The air conditioning "on" door bowden
cable, which extends through the core, will also
be removed at this time.
6. Remove the expansion valve power element from
the low pressure line.
7.
Disconnecting the high pressure and low pressure
lines from the valve, remove the valve from the
core.
8. At this point either the expansion valve, evaporator
core or both may be replaced.
a. If replacing the expansion valve, use new etO"
rings and make the connections carefully to
eliminate possible refrigerant leaks. Position
the power element bulb so that it lies flush with
the low pressure line and has the insulating
material properly in place.
b.
If the evaporator core is to be replaced, it will
be necessary to remove the air conditioning
door bowden cable from the core and install it
in the same location in the replacement core.
If no passage has been provided for this purpose
in the replacement core, a pointed instrument
such as a pencil may be forced through core
vanes at the proper location to provide the re-
quired opening. Also remove the spacer bracket,
nut and screw from the inlet and outlet pipes of
the evaporator core and place them in a like
position on the replacement core.
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-71
SUN-AMBIENT
SENSOR AND COMPRESSOR
CLUTCH SWITCH
HIGH BLOWER
DELAY RELAY
THERMAL
VACUUM
VALVE
Fig.
102-Comfortron Underhood Wiring
use when inspecting a damaged vehicle equipped with air
conditioning.
1.
Remove the drive belt. Cut belt off if necessary.
2.
Visually inspect the condenser, receiver-dehydrator,
compressor, mounting brackets, conditioning unit, all
connecting lines, and all controls to determine the
extent and nature of the damage.
a. No repairs, such as soldering, welding or braz-
ing, should be attempted on the condenser be-
cause of its construction. If the vapor passages
in the horizontal tubes or return bends or mani-
folds have been damaged in any way, the con-
denser should be replaced with a new one.
b.
The receiver-dehydrator should be replaced if
there is any evidence of its having sustained
either internal damage or a fracture at any of
the lines or welded joints or if the system has
been exposed to the atmosphere for an undeter-
mined period of time.
c. Examine the compressor for any visible external
damage.
d. The evaporator should be examined for damage
and, if necessary, removed or replaced or the
entire unit processed where damaged or exposed
to the atmosphere.
e. All connecting lines and flexible hoses should be
examined throughout their entire length for dam-
age.
If damaged in any manner, replace with new
lines.
f. Check all controls and connecting wires for
damage and replace with new parts where needed.
g. Check the clutch pulley for proper operation and
freedom from damage.
3.
Install gauge set.
4.
Purge the system. Pressure should not exceed 3 to
5 pounds.
5. Remove the compressor from mounting and remove
the oil test fitting.
6. Pour out the oil into a clean glass container and ex-
amine it for any foreign substance such as dirt,
water, metal particles, etc. If any of these are
present, the compressor and receiver-dehydrator
should be replaced and the other system components
should be flushed with liquid refrigerant.
7. If the oil is clean and free of any harmful substance,
replace oil with Frigidaire Oil available through
Parts Stock.
NOTE:
If the system components have been
replaced or flushed, replace the full charge of
oil. If not, add no more fresh oil than was
drained in Step 6.
8. Charge up the compressor to drum or can pressure
and leak test the compressor seals prior to in-
stallation of compressor.
9. Reinstall the compressor and evacuate the system
by following the Evacuating Procedure.
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE
6-3
(ROUND) Y~~fll^H
CENTRIFUGAL
A ^k
ADVANCE--jflgKpl
MECHANISM
UB|
CAM
KSK^2
LUBRICATOR
VlSMi
REPLACEMENT
^BK
-^ADJUST
SQUARELY
AND
JUST
TOUCHING
LOBE
OF
CAM
/ROTOR
HBB
__
I^BH^F
?
(SOUARE)
^K^ I /—
CAM
jKft^J / LUBRICATOR
H^T^
CAUTION!
QV NEVER
OIL
•L-^
CAM LUBRICATOR-
REPLACE
WICK
WHEN
NECESSARY
LATERAL
MISALIGNMENT
PROPER
LATERAL ALIGNMENT
Fig.
4- Distributor (V8)
CAUTION: Use extreme care
-when
using tap to
prevent cross threading. Also crank engine sev-
eral times to blow out any material dislodged
during cleaning operation.
7. Install spark plugs with new gaskets and torque to
specifications.
NOTE:
The following are some of the
greatest causes of unsatisfactory spark plug
performance.
•
Installation of plugs with insufficient torque to
fully seat the gasket.
•
Installation of the plugs using excessive torque
which changes gap settings.
•
Installation of plugs on dirty gasket seal.
•
Installation of plugs into corroded spark plug hole
threads.
8^ Connect spark plug wiring.
Service
Ignition System
1.
Remove distributor cap, clean cap and inspect for
cracks, carbon tracks and burned or corroded ter-
minals. Replace cap where necessary.
2.
Clean rotor and inspect for damage or deterioration.
Replace rotor where necessary.
3.
Replace brittle, oil soaked or damaged spark plug
wires.
Install all wires to proper spark plug. Proper
positioning of spark plug wires in supports is impor-
tant to prevent cross-firing.
4.
Tighten all ignition system connections.
5. Replace or repair any wires that are frayed, loose or
damaged.
Us
CORRECT
LATERAL MISALIGNMENT BY
j BENDING
FIXED CONTACT SUPPORT
[NEVER
BEND BREAKER LEVER
Fig.
5 - Point Alignment
Magnetic
Pulse(Breakerless)
Distributor
There are no moving parts in the ignition pulse ampli-
fier, and the distributor shaft and bushings have perma-
nent type lubrication, therefore no periodic maintenance
is required for the magnetic pulse ignition system. Refer
to Section 6Y for an analysis of problems and/or repair
procedures encountered on the Transistorized (Magnetic
Pulse) ignition system.
Standard
(Breaker Point) Distributor
(Figs.
3 or 4)
1.
Check the distributor centrifugal advance mechanism
by turning the distributor rotor in a clockwise direc-
tion as far as possible, then releasing the rotor to
see if the springs return it to its retarded position.
If the rotor does not return readily, the distributor
must be disassembled and the cause of the trouble
corrected.
2.
Check to see that the vacuum spark control operates
freely by turning the movable breaker plate counter-
clockwise to see if the spring returns to its retarded
position. Any stiffness in the operation of the spark
control will affect the ignition timing. Correct any
interference or binding condition noted.
3.
Examine distributor points and clean or replace if
riecessary.
DO
NOT SUCK
IN
TOO MUCH
ELECTROLYTE
TAKE
READING
AT
EYE LEVEL
Fig.
6 - Testing Specific Gravity of Battery
CHEVROtET
CHASSIS SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-8
1
FIELD RELAY^I^p2
"LATCH"
^PFN?^
"P1
TERMINAL
JyJvJCTl^
NO. 2 TERMINAD^5^^^«
NO.
3 TERMINAL ^S5«£
NO.
4 TERMINAL ^^^
m
# / VOLTAGE
¥ REGULATOR
1
ACCESS PLUG TO
VOLTAGE ADJUSTMENT
No 4 TERMINAL
Double Contact
Fig.
2c—Voltage Regulator Assemblies
Transistor
regulator to handle the higher field current and enables it
to absorb the increased inductive voltages of the field
coil with satisfactory contact point life.
The double-contact regulator assembly (fig. 2c) con-
sists of a double contact voltage regulator unit and a field
relay unit. This unit uses two sets of contact points on
the voltage regulator unit to obtain desired field excita-
tion under variable conditions. Internal circuit wiring
diagrams of the double contact regulator are shown in
Figures 3c and 4c.
The transistor regulator (fig. 2c) is an assembly com-
posed principally of transistors, diodes, resistors, a
capacitor, and a thermistor to form a completely static
voltage regulating unit in combination with a conventional
vibrating type field relay.
The transistor is an electrical device which limits the
generator voltage to a preset value by controlling the
generator field current. The diodes, capacitor and re-
sistors act together to aid the transistors in controlling
the generator voltage. This is the only function that the
regulator performs in the charging circuit. The
thermistor provides a temperature-compensated voltage
setting. Wiring diagrams of the transistor regulator are
shown in Figures 3c and 4c.
The voltage at which the generator operates is deter-
mined by the regulator adjustment. The regulator voltage
setting can be adjusted externally by removing a pipe plug
in the cover (fig. 2c) and turning the adjusting arm inside
the regulator. This procedure is explained in the followr
ing section, and permits regulator adjustments without
removing the cover.
FUSIBLE
DOUBLE CONTACT
FUSIBLE LINK-^
JUNCTION HORN
BLOCK RELAY
RESISTOR
Q FIELD Q>
DELCOTRON TR-
TRANSISTOR
FUSIBLE LINK-
Fig.
3c-Circuity - Voltage Regulator Assemblies (Except Corvette)
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-J2
Fig.
8c—Ammeter Method Test Connections
10.
Turn off ignition, disconnect battery ground cable,
and remove all test equipment.
11.
li the Delcotron meets the test specifications, the
problem is not in the generator.
12.
Ti the Delcotron fails to meet the test specifications,
remove it and perform bench tests and make repair
needed.
DELCOTRON DIODE AND FIELD TEST (Fig. 9c)
NOTE:
These tests will indicate good,, shorted
or open field or shorted diode but will not indi-
cate a failed open diode. If output was low and
following tests show good, refer to service op-
erations to determine cause and repair.
1.
Disconnect battery ground cable at battery.
2.
Positive diodes (Test A) connect an ohmmeter be-
tween "R" terminal and "BAT" terminal and note
Fig.
9c-Deicotron Diode and Field Test
reading, then reverse the leads at same terminals
and note this reading. Meter should read high re-
sistance in one direction and low in the other.
3.
Negative diodes (Test B) connect ohmmeter between
"R" terminal and "GRD" and note reading, then
reverse the leads and note this reading. Meter
should read high in one direction and low in the
other.
NOTE:
A high or low reading in both directions
indicates a defective diode.
4.
Open Field Check:
a. Connect an ohmmeter from "F" terminal to
"GRD"
terminal stud and note reading on the
lowest range scale. Meter should read 7 to
20 ohms.
b.
If meter reads zero or excessively high resist-
ance, the Delcotron is faulty.
5. If above tests indicate a defective Delcotron, remove
and completely check Delcotron as outlined under
''Service Operations".
INDICATOR LAMP/INITIAL FIELD
EXCITATION CIRCUIT TESTS (Fig. 10c)
On standard models the indicator lamp circuit provides
initial field excitation (causing lamp to glow). The light
is cancelled by closing the field relay which applies bat-
tery voltage to both sides of bulb (bulb goes out).
The indicator light should glow when ignition switch is
"ON"
and go out almost immediately when engine starts.
Ammeter equipped vehicles use the same initial field
excitation and control circuits as the indicator lamp ex-
cept the lamp is omitted. The continuity tests on both
type vehicles can be made as follows:
If Lamp Fails to Glow or Ammeter Fails to
Function the Possible Causes are:
1.
Faulty bulb or bulb socket.
2.
Faulty ammeter.
3.
An open circuit in wiring, regulator, or field.
4.
A shorted positive diode—(may also cause glow with
ignition switch "OFF").
TEST AS FOLLOWS:
1.
Disconnect connector from regulator and turn
ignition switch to "ON". Connect a test lamp from
connector terminal "4" to ground (fig. 10c, Step 1)
and note test lamp.
a. Lamp fails to glow—check for faulty bulb, socket
or open circuit between switch and regulator con-
nector. Repair as needed.
b.
Light goes on—failure is in regulator, Delcotron,
or wire between "F" terminals on regulator and
Delcotron. Go to Step 2.
2.
Disconnect lamp lead at ground end and connect be-
tween connector "F" and "4" terminals (fig. 10c,
Step 2), and note lamp:
a. Test Lamp glows—problem is in regulator. An
open circuit in regulator or relay is stuck dosed.
See "Service Operations" for repair.
b.
Fails to glow—problem is in wire between "F"
terminals on generator and regulator or infield
windings. Go to Step 3.
3.
Disconnect test lamp at connector "F" terminal and
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-13
F 2 3 4
f 2 3 4
F 2 3 4
Fig.
10c—Initial Field Excitation Circuit Tests
connect to "F" terminal on Delcotron (fig. 10c,
Step 3), and note lamp:
a. Lamp glows-an open circuit in wire between "F"
terminals—correct as needed.
b.
Fails to glow—Delcotron field has open circuit,
see "Service Operations" to repair %
If Lamp Fails to Go Out, or if Ammeter Shows
Discharge the Possible Causes are:
1.
Loose drive belt—adjust as necessary.
2.
Faulty field relay—(see relay test and adjustment).
3.
Defective Delcotron—(see Delcotron output test).
4.
At normal idle—parallel resistance wire open (see
Resistance test). On ammeter models the initial
field excitation wire to "ACC" terminal is open.
5. Switch off—positive diode shorted (see Diode test).
FIELD CIRCUIT RESISTANCE
WIRE CHECKS
The resistance wire is an integral part of the ignition
harness. However, the resistance wire is not solderable;
it must be spliced with a crimp-type connector. It is
rated at 10 ohms, 6.25 watts minimum.
The check for an open resistor or field excitation wire
(connected to the ignition switch "ACC" terminal) is as
follows:
1.
Connect a test lamp from the wiring harness con-
nector terminal "4" to ground as shown in Figure
10c (Step 1).
2.
Turn the ignition switch to the "ON" position and
note test bulb.
a. Test lamp glows—resistance is O.K.
b.
Test lamp does not glow—the resistor is open
circuited—note also that dash lamp does not glow
during this test because series resistance of the
2 bulbs causes amperage to be too low.
VOLTMETER
3 4
WIRING*
HARNESS
CONNECTOR
Fig.
11c—Testing Field Relay
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-14
VOLTMETER
WIRING HARNESS
CONNECTOR
Fig.
12c—Field Relay Closing Voltage Test
FIELD RELAY CHECKS AND ADJUSTMENT
To check for a faulty relay proceed as follows:
1.
Connect a voltmeter into the system at the regulator
No.
2 terminal to ground (fig. lie).
2.
Operate the engine at fast idle (1500 to 2000 rpm) and
observe voltmeter reading.
3.
If voltmeter shows zero voltage at regulator, check
circuit between No. 2 terminal on regulator to "R"
terminal on Delcotron.
4.
If voltage at regulator exceeds closing voltage
Fig.
13c—Adjusting Field Relay Closing Voltage
specification and light remains on, regulator field
relay is faulty (Refer to specifications). Check and
adjust regulator as follows:
CLOSING VOLTAGE ADJUSTMENT
•1.
Make connections as shown in Figure 12c using a 50
ohm variable resistor.
NOTE: This gives us a variable resistance in
series from a hot lead to the relay coil.
2.
Turn resistor to "open" position.
3.
Turn ignition switch off.
4.
Slowly decrease resistance and note closing voltage
of the relay. Adjust by bending heel iron in the man-
ner illustrated in Figure 13c.
OTHER HARNESS CHECKS
Other wires in the charging system harness need be
checked for continuity by use of an ohmmeter or a test
ligjit (12 Volt). Connect the test so the wire in question is
in series in the test circuit.
SERVICE OPERATIONS
Service Procedures described in this section are for
the 5.5" aluminum and 6.2" perforated stator Delcotrons
(fig. 14c). Where important differences are encountered
separate mention will be made of the two generators.
GENERATOR
REMOVAL AND INSTALLATION
1.
Disconnect the battery ground strap at battery to
prevent damaging diodes.
2.
Disconnect wiring leads at Delcotron.
3.
Remove generator brace bolt, (if power steering
equipped, loosen pump brace and mount nuts) then
detach drive belt (belts).
4.
Support the generator and remove generator mount
bolt (6.2" Delcotron uses 2 mount bolts) and remove
from vehicle.
5.
Reverse the removal procedure to install then adjust
drive belt.
PULLEY REPLACEMENT
5.5" Delcotron
Single Groove Pulley
1.
Place 15/16" box wrench on retaining nut and insert
a 5/16" alien wrench into shaft to hold shaft while
removing nut (fig. 15c).
2.
Remove washer and slide pulley from shaft.
3.
Reverse Steps 1 and
2
to install, use a torque wrench
with a crow-foot adapter (instead of box wrench) and
torque the nut to 50 ft. lbs. (fig. 16c).
Double Groove Pulley
1.
Place a 15/16" socket (with wrench flats on the drive
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-29
each capacitor (not illustrated). The capacitor is
shorted if both readings are zero.
6. Resistor Rl: The resistor is open if both readings
are infinite.
7. Resistor R2: Use an ohmmeter scale on which the
1800 ohm value is within, or nearly within, the
middle third of the scale. If both readings are infi-
nite, the resistor is open.
8. Resistor R3: Use an ohmmeter scale on which the
680 Ohm value is within, or nearly within, the middle
third of the scale. If both readings are infinite, the
resistor is open.
9. Resistor R4: Select an ohmmeter scale on which the
15000 ohm value is within, or nearly .within, the
middle third of the scale. If either reading is infi-
nite, the resistor is open. ~
10.
Resistor R5: Use the lowest range ohmmeter scale.
The resistor is open if either reading is infinite.
NOTE:
This resistor on some applications may
be located in the vehicle wiring harness, and not
on the panel board.
11.
Resistor R6: An ohmmeter scale on which the 150
ohm value is within or nearly within, the middle
third of the scale should be used. If both readings
are infinite, the resistor is open.
REASSEMBLY
During assembly, coat with silicone grease both sides
of the flat insulators used between the transistors and
heat sink, and also the heat sink on the side on which the
transistors are mounted. The silicone grease, which is
available commercially, conducts heat and thereby pro-
vides better cooling.'
IGNITION PULSE AMPLIFIER
R-5
C-3 Ju
MAGNETIC PULSE
DISTRIBUTOR
IGNITION SWITCH REPLACEMENT (Figs.
21
i to 23i)
CHEVROLET, CHEVY II AND CORVETTE
1.
Raise hood and disconnect battery ground cable from
battery.
2.
Remove lock cylinder by positioning switch in "off"
position and inserting wire in small hole in cylinder
face. Push in on wire to depress plunger and con-
tinue to turn key counter-clockwise until lock cylin-
der can be removed.
3.
Remove the metal ignition switch nut from the pas-
senger side of the dash using Tool J-7607 (Fig. 21i).
4.
Pull the ignition switch out from under the dash and
remove the wiring connectors.
5. To remove the "theft resistant" connector, the
switch must be out from under the dash as outlined
in Step 4. Using a screw driver unsnap the locking
tangs on the connector from their position on the
switch as shown in Figure 22i. Unplug the connector.
6. Snap the connector into place on a new ignition
switch.
7. Place the switch into position from behind the dash
and install the metal ignition switch nut.
8. Install the lock cylinder.
9. Install the battery cable to the battery and lower the
hood.
CHEVELLE
1.
Disconnect battery ground cable.
2.
Remove ash tray, retainer attaching screws and
retainer.
3.
Remove A/C distributor duct retaining screws and
duct.
Fig.
19i—Pulse Amplifier Internal Circuitry
Fig.
20i—Transistor Checking
CHEVROLET Oi