Service Manual
Table Of Contents
Relay
Part Numbers
48-4700
1
coil
Terminals
30+B7a
Terminals
not
energized
open
closed
energized
closed
open
Table 1
Purpose
The relay monitors current in one circuit.
If
current is present, it flips an SPDT
(single pole, double throw) 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 ener-
gized. 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.
Solenoid
Part Numbers
47-1910
1
I
Purpose
The solenoid‘s purpose is simply to protect the ignition switch from the high
I
I
current drawn by the starter motor.
a
HOW
It
Works
Solenoid The solenoid has really only
two
parts. One is a coil of wire wrapped around
(energized)
10102
an iron core. Whenever 12 volts is applied to the coil, it becomes a magnet.
The other part
is
a steel bar type switch. Because it is made of steel it can
easily handle the high current loads produced by the starter motor.
So
how
does
it
protect the ignition switch? When 12 volts is applied to the coil, it
becomes an electromagnet. This quickly pulls the steel bar toward the con-
tacts and closes the switch. When power is removed from the coil, the spring
loaded bar returns to its “normally open” position. Note: The solenoid closes
and opens the switch very quickly. This protects the ignition switch because
it
minimizes the “arcing” that can damage switches.
Testing
1. Disconnect the solenoid from the wiring harness.
2. Check to insure that terminals “c” and “d” are open.
3.
Apply a known good 12 volt power source to “a” and
“b
terminals. You
should be able to hear the solenoid switch “click” when you make the
connection.
4.
Verify that the switch has closed by making sure that terminals “c” and
“d”
are closed when power
is
applied to terminals “a” and
“b.
3