Power Antenna Woes

[Coan]

The power antenna motor in my '97 quit working last fall. I recently picked up a '95 parts car with a working power antenna. Last night I pulled out the working antenna/motor assembly from the parts car, and without removing the old one I plugged the new one into my '97 and laid it on the trunk to test. It does not work either (in my '97). Works just fine in the '95 though.

Clearly there must be an issue with getting power/signal to the antenna. I checked the motor connector with a multimeter and it seems that one of the 3 pins is getting 12v when the radio is on. Has anybody else encountered this issue before? Could the problem be something inside the stock radio not transmitting the power? My stereo system is 100% stock, complete with buzzy, blown speakers.

I searched, but every thread I found ends with the motor being the problem. Can't seem to find anyone with this issue.