YezusLX
SILVER Star
Reading back through what you have written. It appears that something is causing the OEM Mark Levinson amp to shut off. The most likely offender is a dead short. Dead short is typically a blown speaker. when it moves (an electrical signal passes through it) it connects briefly and then shorts( think a break in connection) causing the amp to protect itself. The other likely cause could be the amp itself has a short. Meaning dead channel, or bad ground. If it is a bad ground it could be from the new harness (unlikely) or the radio chassis is not grounded. Or again a bad channel as in speaker blown. Hunting for speakers starts by unplugging all and then plugging them in one at a time until the amp shuts down. If I was a betting man, I would say the subwoofer or center channel. The sub likes to dry out and go to pieces and does take lots of abuse. The center channel sits in the sun all day every day drying out as well. I hope that helps a little bit.