I am installing a XM commander. I connected the BATT and ACC leads to the JVC radio harness. The ground is connected to the same spot my amp is connected to. All connections seem ok, Test light show the correct power the leads. The radio and amp work fine but the damn commander wont turn on. WTF? Is it broken?

 

DId you try holding the power button down? Change the ground or the power and see if you have different results.

 

This may sound silly but have you tried unplugging it and pluging it back in. Sometimes changers and XMs do some crazy things and this resets them.

 

also too if it has a tiny reset button on the controller try pressing it, alot of the times when i install pioneer FM mod cd changers after everything is hooked up, it wont power on from the controller until I hit the reset button on the changer, then all is well.