small antenna problem after stereo install

[CusCo_S14]

the small problem i have is that my power antenna used to go down when I would play cd and go up when i listen to the radio, but now that I had a eclipse monitor installed it stays up all the time,is there a way to fix it back to the way before the install. like I said small problem.

[Defiant]

I don't know that after-market head units have that bit of jimcrackery in their firmware. Mine also just runs it up, regardless of mode.