Service Manual

Workman HD Series Page 8 − 13 Electrical System
Brake Switch(s)
The brake switch is is attached to the frame under the
dash (Fig. 12). A switch with one set of normally closed
terminals is used on 2WD units. A switch with one set of
normally closed terminals and one set of normally open
terminals is used on 4WD units (Fig. 13).
When the brakes are not applied, the brake pedal press-
es the brake switch plunger to open the normally closed
terminals. When the brakes are applied, the pedal
moves away from the brake switch plunger, the termin-
als switch to the normally closed state, and a current
path to illuminate the stop lights is made.
The additional normally open terminals of the brake
switch used in 4WD units are closed when the brakes
are not applied. In this position current is allowed to pass
through the switch to energize the 4WD relay. When the
brakes are applied, the pedal moves away from the
brake switch plunger, the terminals switch to the normal-
ly open state, and the current path to the relay is broken.
Testing
1. Park vehicle on a level surface, shut engine off, re-
move key from ignition switch and apply parking brake.
Locate the brake switch (Fig. 12).
2. Disconnect the wire harness connector from the
brake switch.
3. Use a multimeter (ohms setting) to test continuity
across the switch terminals.
2WD UNITS: Test continuity across the two (2)
switch terminals. There should be continuity (zero
ohms) when the brake pedal is depressed and there
should not be continuity (infinite ohms) when the
brake pedal is released.
4WD UNITS:Test continuity across the two (2) nor-
mally closed switch terminals (Fig. 13). There
should be continuity (zero ohms) when the brake
pedal is depressed and there should not be conti-
nuity (infinite ohms) when the brake pedal is re-
leased.
Test continuity across the two (2) normally open
switch terminals (Fig. 13). There should not be
continuity (infinite ohms) when the brake pedal is
depressed and there should be continuity (zero
ohms) when the brake pedal is released.
4. After switch testing is completed, connect the wire
harness connector to the brake switch.
Figure 12
2
1
1. Brake pedal 2. Brake switch (2WD units)
Figure 13
1
1. Brake switch (4WD units)
NORMALLY
CLOSED
NORMALLY
OPEN
Electrical
System