Buick LeSabre 1965 Service Manual page 591

ELECTRICAL SYSTEMS
REGULATOR TESTING 1 0 - 2 1
Air Temperature at
Regulator . . .
Voltage Setting .
85° 105° 125° 145° 165°
13.8-14.6 13.7-14.5 13.5-14.3 13.4-14.2 13.2-14.0
Figure 10-21—Voltage Regulator Settings
5. Reconnect b a t t e r y ground
cable. Connect a voltmeter across
battery.
6. Turn on all possible acces-
sory load. Apply parking brake
firmly. Start engine. Adjust en-
gine idle to exactly 500 RPM in
Drive. At this engine speed, gen-
erator output should be 10 am-
peres or over. Shift transmission
to Park. Increase engine speed to
exactly 1500 RPM; output should
be 30 amperes or over. Shut off
engine. Turn off all accessories.
7. If output is low in either of
the above tests, try supplying
field directly to cause full gen-
erator output. Unplug connector
from generator. Connect a jumper
such as Adaptor J-21053 from
generator " F " terminal to "BAT"
terminal. Retest as described in
Step 6. If output is still low, gen-
erator is faulty and must be re-
moved for b e n c h tests and
repairs. To see if fault is in the
diodes, test diodes as described
in subparagraph b.
8. If output (using field jumper)
is now okay, trouble is in the reg-
ulator or wiring harness. Clean
and test regulator. Check all wir-
ing connections.
9. Remove field jumper and re-
install vehicle field connector.
b. Test Generator Diodes
(On-The-Car)
1. Disconnect ground cable from
battery.
2. Disconnect battery lead and
relay - field connector f r o m
generator.
3. To test all three positive
diodes, connect a test light such
as J-21008 from the generator
" R " terminal to the "BAT" ter-
minal and observe test light; then
reverse test ligjht connections
and again observe light. The test
light should light in only one of
the two directions.
4. To test all three negative
diodes, connect the test light from
the " R " terminal to the "GRD."
terminal and observe test light;
then reverse test light connec-
tions and again observe light. The
test light should light in only one
of the two directions.
5. If the test light lights in both
directions in either Step 3 or
Step 4, there is at least one de-
fective diode. Remove generator
and disassemble on bench. Test
diodes individually and replace
as necessary.
c. Test and Adjust Voltage
Regulator Setting
1. Test current output as de-
scribed above. See Figure 10-20.
Leave all test instruments in
place, but make sure field jumper
is removed, if used.
2. Install a thermometer such as
Gauge J-8529 near regulator.
3. Run engine at approximately
1500 RPM for 15 minutes. Make
sure all electrical load except
ignition is turned off.
4. Check ammeter reading. For
an accurate voltage setting check,
ammeter must read between 3 and
10 amperes. (If ammeter reading
is still high after 15 minutes, it
may be necessary to substitute a
ADJUSTING SCREW
(TURN TO ADJUST
VOLTAGE SETTING)
Figure 10-22—Adjusting Voltage
Regulator Setting
fully charged battery.) Momen-
tarily increase engine speed to
approximately 2000 RPM and read
voltmeter and thermometer. See
Figure 10-21 to determine if
upper voltage regulator setting is
within limits for the existing
temperature. If setting is within
limits and battery condition has
been satisfactory, voltage setting
should not be disturbed.
5. If voltage regulator setting is
out of limits, make a note of
change required to put voltage in
middle of specified range. Re-
move regulator c o v e r , lifting
cover carefully straight up. CAU-
TION: If the cover touches either
regulator unit, the resulting arc
may ruin the regulator assembly.
6. With cover off, voltage read-
ing will change considerably.
Starting with the changed voltage
reading, increase or decrease
voltage (the amount determined in
Step 5) as shown in Figure 10-22.
CAUTION: Always make final ad-
justment by increasing spring ten-
sion to assure contact between
screw head and spring support.
7. After making an adjustment,
replace cover carefully and re-
check voltage setting of regulator.