Electric Pto Switch; Pto Relay - Craftsman 28906 Professional Shop Manual

ELECTRICAL SYSTEM
Electric PTO switch
Understanding the electric PTO switch
In A-Com, power is supplied to the PTO switch
from the A1 terminal of the ignition switch
through a red wire. when the PTO switch is
turned on this completes the circuit to allow
power to go to the PTO clutch. It is a normally
opened (NO) set of contacts.
B-COM is in the safety shut-down circuit. It is a
normally opened (NO) set of contacts. A circuit is
completed from the NO terminal on the PTO
relay through the white wire with black trace to
the E-PTO terminal on the RMC module and the
PTO relay coil through the yellow wire with black
trace when the contacts are closed. This gives
the RMC module the ability to turn-off the PTO
clutch.
C-COM is in the starter inhibit circuit. It is a nor-
mally closed (NC) set of contacts. When the
PTO is OFF, and the contacts are closed, power
coming from the brake switch (key switch in
START, brakes ON) through the oranqe wire
with black trace is passed on to the trigger termi-
nal on the starter solenoid through the orang_g_
wire with white trace.
..........................
_ IL A
Figure 7.9
NOTE: The top terminals are showing normally
closed at rest and the middle terminals are nor-
mally open at rest
NOTE: There are three contacts on the right side
in the C-COM. For this application the normally
opened (NO) contact is used.
PTO relay
The PTO relay is located on the main harness, under-
neath the electric PTO switch. See Figure 7.10.
Figure 7.10
The PTO relay has 5 wire going to it:
• The red wire is battery power from the A1 termi-
nal of the key switch. It is connected to the coil of
the relay.
• The qreen wire is a ground wire. It is connected
to the common terminal of the relay.
• The white wire connects the NC terminal of the
relay to the ground side of the PTO clutch.
• The white wire with black trace connects the NO
terminal of the relay to the "B" circuit terminals of
the electric PTO switch.
The yellow wire with black trace connects the
coil of the relay to the "B" circuit terminals of the
electric PTO switch.
To access the PTO relay, remove the fuel tank by fol-
lowing the step described in Chapter 2: Engine Related
Parts.
NOTE: The PTO relay should be mounted so
that the terminals face down. This helps to keep
water out of the relay. The PTO relay connector
can be filled with petroleum jelly before inserting
the relay. This will also help to keep moisture out
of the relay.
NOTE: Electrical tape that is wrapped tightly
around the relay can prevent the relay from
operating properly.
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