Sharp MX5050 5070 weird fuser jam won't reset

[Jammed]

Customer removes the jams. Close all doors. Jam code remains. No paper jammed anywhere inside the machine. Jam will not reset. Happened more then once. Happened on more then one of these same model machines. Suspecting the front door / side door switches.
Has anyone else seen this? What's the fix. TIA
We have been able to reset with unplugging all accessories, rebooting, plugging back in finisher, pedestal, even the right hand door ribbon cables, eventually resets box.
Strange but true.
-Steve

[ZOOTECH]

Customer removes the jams. Close all doors. Jam code remains. No paper jammed anywhere inside the machine. Jam will not reset. Happened more then once. Happened on more then one of these same model machines. Suspecting the front door / side door switches.
Has anyone else seen this? What's the fix. TIA
We have been able to reset with unplugging all accessories, rebooting, plugging back in finisher, pedestal, even the right hand door ribbon cables, eventually resets box.
Strange but true.
-Steve

Any jam codes logged?

[mike2565]

We had one doing this it ended up being the sensor right below the secondary transfer unit. sensor 2tpd.