Can't get AM Band

Hi Everyone,
I've just installed a Sony CDX-4050 CD player in my car and it plays CDs and I can get FM Band but no AM Band.
It looks like there is only one antenna plug.
Is there something I've done wrong or maybe the unit is faulty?
Any help greatly appreciated.
Regards
Gary.

there is only one antenna for both AM and FM. Look and make sure you don't have the AM band set to "european"

There is a little switch on the bottom of this unit to change the settings for AM channel increments. I have made sure it is set correctly but still no sound for AM. I'll keep trying.
Thanks for your response.