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ELECTRICAL
7.3
NEUTRAL POSITION INDICATOR
SWITCH
TEST
1. Verify that the transmission is in neutral and the
key is off. Connect an ohm meter lead to the
switch lead and one to engine ground. Meter
resistance should read in megaohms or no
continuity.
2. Shift the transmission into gear. The ohm meter
should show continuity.
3. If there is no continuity with the transmission in
gear, remove the switch and re--test manually.
Inspect the shift drum contact pin and spring for
proper function. If no problems are found, inspect
the wiring, bulb and harness connections.
COOLANT TEMPERATURE
SENSOR TEST (HOT
LIGHT)
With the ignition switch (and engine stop switch) “ON”,
power is delivered to the hot light via the Red/White
wire. The Blue/White wire (ground) out of the light
socket is connected to the coolant temperature
sensor on the cylinder head. In normal operating
conditions, the temperature sensor is non-conductive
(open). If engine coolant reaches the specified
temperature, the sensor becomes conductive
completing the ground path for the light.
With engine cold, disconnect lead and measure
resistance of sensor between connector terminal and
ground. There should be no continuity or very high
resistance (megohms).
Hot Light On
221q F (105q C)
FAN CONTROL CIRCUIT
OPERATION /
TESTING
The fan switch is located on the radiator. Power is
supplied to the fan switch via the Red/Black wire when
the ignition key is ON. When the fan switch reaches
the specified temperature, it becomes conductive and
sends power to the fan motor through to the
Orange/Black wire. The ground path for the fan motor
is through the Brown harness wire.
CAUTION: Keep hands away from fan blades
during this procedure. Serious personal injury
could result.
The fan switch may not function or operation may be
delayed if coolant level is low or if air is trapped in the
cooling system. Be sure cooling system is full and
purged of air. Refer to Maintenance Chapter 2 for
cooling system information.
FAN CONTROL SWITCH
BYPASS
TEST
1. Disconnect harness from fan switch on radiator.
2. Place a jumper wire between the Red/Blk and
Org/Blk wires in the connector.
3. With the parking brake on, turn the ignition key
(and engine stop switch) “ON”. The fan should
start running.
4. If the fan runs with the jumper wire installed,
check the fan control switch and connector
terminals. If the fan does not run or runs slowly
with the jumper wire installed, check the fan motor
wiring, ground, and motor condition (refer to Fan
Motor Current Draw). Repair or replace as
necessary.
FAN MOTOR CURRENT DRAW
Connect ammeter leads to
each service tool terminal
Connect BRN Wires
A current draw test will provide a good indication of fan
motor condition. A worn or damaged fan motor will
draw more current, which causes a reduction in blade
speed and reduced cooling.
1. Turn key to off. Disconnect harness from fan
switch on radiator.
2. Place a jumper wire between the Red/Blk and
Org/Blk wires in the fan switch connector.
3. Disconnect the fan and place a jumper wire
between the brown wires in the connectors. This
will provide a ground path to the fan.
4. Place a DC ammeter in series as shown in the
Illustration.
5. Be sure fan blade is free to rotate.
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