Relay; Purpose; Location; How It Works - Toro 22317 Service Manual

CHAIN DRIVE/ELECTRICAL

Relay

Purpose

The chain drive wheeled traction unit uses one relay to
direct current flow to the start circuit of the unit.

Location

The relay is located on the right hand side, bolted to the
lower frame assembly, next to the engine (Fig. 0861).

How It Works

A relay is an electrically actuated switch.
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. Switch: Terminals 30, 87 and 87a are actually
part of a single pole, double throw (SPDT) switch.
Terminal 30 is the common lead. The switch is spring
loaded so that 30 and 87a are not connected when
the coil is not energized. When the coil is energized
the switch is "thrown" and 30 and 87 are connected
(Fig. 0937).
4/5-2
Fig. 0861 DSC-0823a

Testing

1. Disconnect the relay from the harness.
2. Verify the coil resistance between terminals 85 and
86 with a multimeter (ohms setting). Resistance
should be from 70 to 90 ohms. There should be
continuity between terminals 87a and 30 (Fig. 0862).
30
85
Relay
(not energized)
3. Connect the multimeter (ohms setting) leads to relay
terminals 30 and 87. Ground terminal 86 and apply
+12 VDC to terminal 85. The relay should make and
break continuity between terminals 30 and 87 as
12 VDC is applied and removed from terminal 85
(Fig. 0862).
4. Connect the multimeter (ohms setting) leads to relay
terminals 30 and 87a. Apply +12VDC to terminals
85. With terminal 86 still grounded, the relay should
break and make continuity between terminals 30
and 87a as 12 VDC is applied and removed from the
terminal (Fig. 0862).
5. Disconnect voltage and multimeter leads from relay
terminals.
Toro Wheeled CUL Service Manual
87a
87
86
Fig. 0862 xl relay 1