Fault Phenomenon: SANY SY5308THB lights function normally when cold. After nighttime operation for 1 hour (operating temperature), the headlights flicker and eventually turn off, with a dashboard lighting alarm.

Troubleshooting Process:
– Checked headlight bulbs: filaments intact, not burnt.
– Checked light switch: contacts good, no oxidation.
– Checked light harness ground: ground resistance normal when cold.
– Measured light harness voltage at operating temperature: found excessive voltage drop.

Root Cause: The light harness connector oxidizes due to heat, leading to excessive contact resistance.

Required Parts: Headlight harness and connector repair kit.