Check Stator Output Voltage; Check Generator Output Voltage; Check For Loose Connections; Check For Field Circuit Drain - Ford LRG-423 Service Manual

GENERATOR DIAGNOSIS AND TESTING (Continued)
PINPOINTTEST B: INDICATOR LAMP ON, ENGINE RUNNING (Continued)
TEST STEP
B5

CHECK STATOR OUTPUT VOLTAGE

Start engine.
l
Measure voltage at the S terminal on the back of the
l
generator.
Is voltage at least l/2 of battery voltage?
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B6
Measure voltage at the B+ terminal on the back of the
l
generator with the engine running at 2000 RPM and all
accessories turned off.
Is voltage greater than 15.5 volts?
l
TEST STEP
Cl

CHECK FOR LOOSE CONNECTIONS

Check these connections for corrosion, loose or bent
l
pins, or loose eyelets:
Three-pin voltage regulator connector.
Are all connections clean and tight?
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c 2

CHECK FOR FIELD CIRCUIT DRAIN

Turn key to OFF position.
l
Measure voltage at test point F on the voltage
l
regulator.
Is voltage at test point F equal to battery voltage?
c 3
Start engine.
l
Check the generator fuse loose connection by wiggling
l
the fuse with the engine running.
Does indicator lamp flicker?
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c 4 CHECK A CIRCUIT CONNECTIONS
With engine running, connect test point A on the
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voltage regulator to the positive (+) battery post using a
jumper wire.
Does indicator lamp flicker?
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c 5 CHECK BRUSH HOLDER SCREWS
Remove generator from unit.
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Check the brush holder screws, located on the voltage
l
regulator (test points F and A).
Are the brush holder screws tight?
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C6 CHECK FOR GROUNDED SLIP RING
Remove voltage regulator.
l
Measure resistance from each generator slip ring to the
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generator housing.
Is resistance from either slip ring to housing less
l
than 200 ohms?
PINPOINTTEST C: INDICATOR LAMP FLICKERS/INTERMITTENT
Auxiliary Systems
RESULT
Yes
No
Yes
No
RESULT
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
ACTION TO TAKE
GO to B6.
GO to Pinpoint Test A to find
the cause of low generator
output.
GO to Pinpoint Test D to find
the cause of high output
voltage.
REPLACE voltage regulator
ACTION TO TAKE
GO to C2.
CLEAN or REPAIR
connections as required.
GO to C3.
GO to C5.
REPAIR loose fuse
connection.
GO to C4.
REPLACE voltage
regulator. If problem still
exists, REPLACE generator.
REPAIR poor connection in
Circuit 36 (Ye).
GO to C6.
TIGHTEN screws to
specification. 2.8-4.0 Nom
(25-35 In-Lb).
If grease or dirt has
accumulated near the slip
rings, CLEAN the slip rings
and RECHECK resistance. I <
still less than 200 ohms,
REPLACE generator.
REPLACE voltage regulator