INSTRUMENT PANEL TROUBLESHOOTING

TM 10-3930-638-24&P

2-25. INSTRUMENT PANEL TROUBLESHOOTING

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

NOTE

Refer to paragraph 2-13 for OIL PRESSURE gage and FUEL LEVEL gage

troubleshooting, and paragraph 2-22 for ALTERNATOR warning light

troubleshooting. Other switches and lights are covered in the paragraphs that

cover the systems of which they are a part.

1. WARNING LIGHTS INOPERATIVE

Step 1. Turn and hold IGNITION switch key at LAMP TEST position.

If at least one warning indicator (ENGINE TEMPERATURE, TRANSMISSION TEMPERA-

TURE, or HYDRAULIC FILTER) is on, check for open circuit in wiring, connector, or isolation

diode between inoperative warning light and IGNITION switch. If circuit check is satisfactory,

replace warning light (para 2-28e).

If at least one warning indicator is not on. turn IGNITION switch kev to ON position and

check if a slight buzz can be heard at electric fuel pump. If slight buzz indicating electric fuel pump

operation is not heard, troubleshoot IGNITION switch (para 2-25, MALFUNCTION 2). If slight

buzz is heard, check for open circuit in wiring between TRANSMISSION TEMPERATURE

warning light and 6 ampere circuit breaker. If circuit check is satisfactory, proceed to step 2.

Step 2. Disconnect wires from engine temperature, transmission temperature, oil pressure and hydraulic

filter switches.

Temporarily connect a jumper from each wire to vehicle ground and turn IGNITION switch key to ON

position.

ENGINE TEMPERATURE, TRANSMISSION TEMPERATURE, OIL PRESSURE and

HYDRAULIC FILTER warning lights should be on.