Fault Phenomenon: Co-Nele KNL5700 safety functions are normal when cold. During nighttime construction (operating temperature), the lighting system fails, lights flicker, and eventually go out.

Troubleshooting Process:
– Checked light bulbs: filaments intact, not burnt.
– Checked light switch: switch contacts normal, no oxidation.
– Checked lighting harness: harness intact, good grounding.
– Measured lighting system voltage at operating temperature: found voltage unstable.

Root Cause: Aging of components in the lighting system rectifier due to heat leads to unstable output.

Required Parts: Lighting system rectifier assembly.