John Deere – 1023E, 1025R and 1026R – Lighting Circuit Diagnosis 1023E

– Machine parked, park brake locked
– Battery fully charged
– Power Circuit tested and functioning
– Transmission in NEUTRAL
– PTO switch OFF
– Digital voltmeter (–) lead to battery negative post
– Digital voltmeter (+) lead to designated test point
– Key switch position OFF or as directed
– Light switch and Turn Signal switch position as directed

Refer to Lighting Circuit – 1023E for circuit schematic.

In rare cases, the instrument cluster may be faulty. Test all applicable power, grounds, wires, connectors and components before replacing ICC.