Electrical System
377
Starter Relay Circuit Test
A starter relay that does not close or drops out too soon can be caused by high resistance or an open cir-
cuit in the control circuit. Perform the starter relay circuit test as follows (Figure 9-18):
1. Disconnect the “S” lead
from the solenoid to prevent
the engine from cranking,
and wrap terminal with a rag
to keep from grounding.
2. With the ignition rotary
switch selected to IGNI-
TION, push the start button.
(If working from the engine
compartment, flip the IGNI
-
TION switch to the ON po-
sition and push the ENGINE
START button on the Rear
Run Box.) You should hear
the starter relay close. If not,
proceed to next step.
3. Connect the voltmeter to
the battery cable ends at the
starter (voltmeter connection
1).
4. Push the start button and
measure the battery cable
voltage.
5. Connect the voltmeter to
the two small terminals of
the starter relay (voltmeter
connection 2). If only one
small terminal exists, use the
starter relay bracket for the
ground connection.
6. Push the start button and measure the starter relay voltage.
7. Determine control circuit loss by applying the following formula:
Battery positive (+) terminal to relay
to battery negative (–) termanl
Battery Cable Voltage – Starter Relay Voltage =
VOLTMETER
STARTER RELAY
START BUTTON
IGNITION SWITCH
BATTERY
+
20-800-85
BATTERY
+
BATTERY
+
S
2
1
Figure 9-18, Starter Relay Circuit Test
Summary of Contents for LOW FLOOR
Page 18: ...Specifications 18...
Page 58: ...Preventive Maintenance 58...
Page 110: ...Engine 110...
Page 138: ...Transmission Driveline Rear Axle 138...
Page 182: ...Suspension 182...
Page 260: ...Air System 260...
Page 420: ...Electrical System 420 Deutsch DT Series Connectors...
Page 421: ...Electrical System 421...
Page 422: ...Electrical System 422 Deutsch HD 10 Series Connectors...
Page 423: ...Electrical System 423...
Page 424: ...Electrical System 424 Deutsch HD 30 Series Connectors...
Page 425: ...Electrical System 425...
Page 442: ...Heating Air Conditioning 442...
Page 492: ...Body and Interior 492 Figure 11 33 USSC Seat Assembly...
Page 493: ...Body and Interior 493 Figure 11 34 USSC Seat Suspension Assembly...
Page 495: ...Body and Interior 495 Figure 11 37 Seat Air Connections...