قطع شدن سیم در دسته‌سیم درب

A conductor broken where the harness crosses into a door or a flap. Every wire there is flexed with each opening, tens of thousands of times, so this is a fatigue failure rather than damage.

The break is inside intact insulation, which is what makes it hard: the loom looks perfect and the conductor is severed within the rubber concertina between body and door. The fault follows door position — working with the door shut and failing when opened, or the reverse — which is the diagnostic signature and no static test reproduces it. Flex the concertina by hand while monitoring the circuit. Repair the whole flexing section rather than the one broken strand, since neighbouring conductors are the same age and the next is usually not far behind.