How would I go about confirming this diagnosis? I should note that if I disconnect the antenna wire from the tuner module, reception gets *way* worse -- so it's not like the antenna connection is completely dead.

One other data point I discovered today is that on the AM dial, no matter what station I select, I get a faint signal of one particular station at 1020 kHz. That station happens to be the strongest in my area, but I find it strange that I can hear it even if I go all the way to 1400 kHz I can still hear that same station.

My antenna is in my car's glass, if that makes any difference...