Textron JACOBSEN GP400, Technical/Repair Manual

Page: 88 / 354

4-36 4252490-Rev A
ELECTRICAL
4
Troubleshooting
Power Circuit
Symptom:
Machine does not power up.
Glow Plug Circuit
Symptom: Glow plugs do not get hot.
Start Circuit
Symptom: Starter motor solenoid does not engage.
Probable Cause Remedy
Faulty wiring. Check wiring and connections at the battery posts.
Check wiring and connections between the battery negative (–) cable and ground.
Faulty battery. Replace battery with a known good battery.
Insufficient circuit voltage. Check for approximately 12 volts at key switch terminal A. If the voltage is not
approximately 12 volts, diagnose the insufficient voltage issue.
Faulty key switch. Turn the key switch to the run position; check for 12 volts at key switch terminal B. If the
output is not approximately 12 volts, test the key switch. (See “Key Switch Test” on
page 4-42.)
Probable Cause Remedy
Faulty 40A fuse. Test the 40A glow plug fuse. (See “Fuses Test” on page 4-41.)
Insufficient circuit voltage. Turn the key switch to the start position; check for approximately 12 volts at glow plug
relay terminals 30 and 86. If the voltage is not approximately 12 volts, diagnose the
insufficient voltage issue.
Faulty glow plug relay. Test the glow plug relay. (See “Relays Test” on page 4-41.)
Faulty glow plugs. Substitute the glow plugs with known good glow plugs.
Probable Cause Remedy
Faulty battery. Replace battery with a known good battery.
Insufficient circuit voltage. Turn the key switch to the start position; check for approximately 12 volts at the starter
electrical connectors. If the voltage is not approximately 12 volts, diagnose the
insufficient voltage issue.
Turn the key switch to the start position; check for approximately 12 volts at starter relay
terminals 30 and 86. If the voltage is not approximately 12 volts, diagnose the
insufficient voltage issue.
Faulty start relay. Test the start relay. (See “Relays Test” on page 4-41.)
Faulty seat switch. Test the seat switch. (See “Seat Switch Test” on page 4-46.)
Faulty mow switch. Test the mow switch. (See “Rocker Switches Test” on page 4-43.)
Faulty mow/transport switch Ensure mow/transport switch is properly adjusted and verify LED on mow/transport
switch illuminates when switch is activated. Adjust and/or replace switch as
necessary. (See “Mow/Transport Switch Adjustment” on page 4-49.)
Faulty park brake switch. Substitute the park brake switch with a known good park brake switch.
Faulty key switch. Test the key switch. (See “Key Switch Test” on page 4-42.)
Faulty starter. Substitute the starter with a known good starter.