Textron JACOBSEN GP400, Technical/Repair Manual

Page: 90 / 354

4-38 4252490-Rev A
ELECTRICAL
4
Work Light Circuit
Symptom: Work lights do not turn on.
Instrumentation Circuit
Lamp and Audible Alarm Check Circuit
The control module provides a lamp and audible alarm check circuit. When the key switch is turned to the run position,
the control module turns on the following:
• Alarm light
• Horn (one chirp)
After the lamp and audible alarm check circuit, the oil pressure light remains on because the engine is not operating. If
this light fails to turn on, check the LED.
Symptom: Engine oil pressure light stays on with engine running.
Symptom: Alarm light does not come on.
Symptom: Hydraulic filter pressure light is on with the key switch in the run
position (engine off).
Symptom: Hydraulic filter pressure light is on with the key switch in the
run position (engine on).
Probable Cause Remedy
Faulty work light(s). Substitute the work light(s) with a known good work light(s).
Faulty 15A fuse. Test the 15A light switch fuse. (See “Fuses Test” on page 4-41.)
Faulty work light switch. Test the work light switch. (See “Rocker Switches Test” on page 4-43.)
Probable Cause Remedy
Low engine oil pressure. Check engine oil level.
Faulty engine oil pressure switch. Substitute the engine oil pressure switch with a known good engine oil pressure switch.
Probable Cause Remedy
Faulty alarm light. Substitute the alarm light with a known good alarm light.
Insufficient circuit voltage. Turn the key switch to the run position; check for approximately 12 volts at control module
terminal J2-6. If the voltage is not approximately 12 volts, diagnose the insufficient
voltage issue.
Probable Cause Remedy
Faulty hydraulic filter pressure switch. Substitute the hydraulic filter pressure switch with a known good hydraulic filter pressure
switch.
Probable Cause Remedy
High hydraulic oil pressure. Check hydraulic oil level.
Dirty hydraulic oil filter. Replace hydraulic oil filter.
Faulty hydraulic filter pressure switch. Substitute the hydraulic filter pressure switch with a known good hydraulic filter pressure
switch.