I have a '95 SC400 with the Nakamichi stereo.

I'm running a line from the oem remote amp to my aftermarket amplifier and it used to work... sometimes it would cut out. well, it's quit working lately. The amp is still getting warm and i checked the power with a voltometer and it was all good. but i tested the remote line and it was hovering around 10.5 volts. i then tested the remote line from the old cell phone that came in the car... it also wouldn't turn on the amp.

any idea on what i should try to get the amp to turn on and maybe how to fix my remote line?

 

I would suggest you get another 12V ACC wire to hook up to your remote turn on your amp.