Service Manual
Testing
1. Make sure that the battery is fully charged. (The voltage across the
battery terminals should be 13.6 volts or more.)
2. Insert an ammeter (capable of measuring 20 amps) in series with the
B+ lead coming from the voltage regulator.
3. Observe the charging current with the engine running at 3600 rpm (it
should be low).
4. Attach a 2.5 ohm, 100 watt resistor across the battery terminals to
simulate a load. If the reading on the ammeter goes up, the charging
system is OK, otherwise proceed to the next step.
5. Remove the connector from the rectifier/regulator. With the engine
running at 3600 rpm, measure the voltage across the stator terminals.
If the voltage is greater than 28 volts, the stator is OK and the regulator
is bad. Otherwise, see the alternator section for further testing
information.
BATTERY CHARGES CONTINUOUSLY AT HIGH RATE: Measure the
voltage from B+ to ground using a VOM on D.C. scale. If the voltage is
more than 14.7 volts, replace the regulator.
Part Numbers
48-4700, 116397
Purpose
The relay monitors current in one circuit. If current is present, it flips an
SPDT switch to the other position.
How It Works
A relay is actually two simpler parts working together.
1. Coil: Terminals 85 and 86 are connected to a coil. Applying 12 volts to
these terminals energizes the coil turning it into an electromagnet.
2. SPDT Switch: Terminals 30, 87, and 87a are all actually part of a single
pole, double throw switch. Terminal 30 is the common lead. The switch
is spring loaded so that 30 and 87a are closed when the coil is not
energized. When the coil is energized, the switch is “thrown” and 30
and 87 connected. For a simpler explanation, see below:
Testing
1. Disconnect the relay from the circuit.
2. Verify the “not energized’’ conditions above with a VOM.
3. Apply 12 volts to terminals 85 and 86 to energize the coil.
4. Verify the “energized” conditions above with a VOM.
5. Replace relay if any of the conditions in Table 1 were not met.
Relay
Coil Terminals
30 + 87
Terminals
30 + 87a
Not
Energized
Open Closed
Energized Closed
Open
Table 1
Glossary
GLOSSARY
3-16 Demystification Guide