Engine shuts off when engaging clutch or releasing brake

I have a craftsman PO1538, 2003

I ckd the interlock seat switch/clutch switch with voltmeter, tested OK! I went farther and ckd drive belt area for problems, replaced a pulley; with the drive belt off, I started the mower and went to release the brake and it instantly shuts off; I lift the lever that engages the blades, it shuts off; I returned the clutch lever to depress the interlock swith and holding the brake, I stood up off of the seat and it did not shut off!

Is this a wiring harness problem/short?!