Motors suck down current pretty readily. I second checking out the power antenna. The way the NA antenna works is stupidly simple. There's a little plastic disc with some conductive coating on most of it but there's a little pie slice where there's none. The motor runs up or down until the contact hits that dead point. I'd assume since that worked well for the NAs the NBs are probably the same way. There's a little access panel on the side with two screws where this will be clearly visible once removed.

 

wouldnt he hear the entenna wirring away they arent exactly silent.

 

Also a valid point . There's a little box with some relays and ICs in it that's on the antenna that controls it's movement along with the limit switch. They'd still be powered up if they weren't told to cut it out.

To the OP:
How large was the current draw?