Service manual

Groundsmaster 3280−D/3320 Page 6 − 27 Electrical System

Fuel Pump Relay (Groundsmaster 3320)

The Groundsmaster 3320 uses a relay to energize the

fuel pump. The fuel pump relay is attached to the sup-

port bracket inside the right side frame near the fuel filter.

Testing

NOTE: Prior to taking small resistance readings with a

digital multimeter, short the meter test leads together.

The meter will display a small resistance value (usually

0.5 ohms or less). This resistance is due to the internal

resistance of the meter and test leads. Subtract this val-

ue from the measured value of the component you are

testing.

1. Locate relay and disconnect the machine wire har-

ness connector from the relay.

2. Using a multimeter (ohms setting), measure coil re-

sistance between terminals 85 and 86 (Fig. 37). Resist-

ance should be between 70 and 90 ohms.

3. Connect multimeter (ohms setting) leads to relay ter-

minals 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.

4. Disconnect voltage from terminal 85 and multimeter

lead from terminal 87.

5. Connect multimeter (ohms setting) leads to relay ter-

minals 30 and 87A. Apply +12 VDC to terminal 85. The

relay should make and break continuity between termi-

nals 30 and 87A as +12 VDC is applied and removed

from terminal 85.

6. Disconnect voltage and multimeter leads from the

relay terminals. Connect relay to machine wire harness.

Figure 37

87A 87

Electrical

System