Fault Phenomenon: SANY SY5308THB electrical system functions normally when cold. During prolonged high-current operation (operating temperature), the wiring harness smokes, a burning smell appears, and eventually an open circuit occurs.

Troubleshooting Process:
– Checked electrical load: load within rated value.
– Checked fuses: fuse rating correct.
– Checked wiring harness routing: no rubbing damage.
– Measured wiring harness connector temperature at operating temperature: found connector overheating.

Root Cause: Poor crimping of the wiring harness connector causes excessive contact resistance under high current, leading to overheating and self-ignition.

Required Parts: Complete vehicle wiring harness and connector repair.