Is there a connection between the TV and the Sony receiver? Audio out of the TV to an AUX input on the Sony?. Usually there will be a red & white RCA type cable from the TV to the Sony. A better solution is an optical audio cable. You will need to select the input on the Sony that the TV is hooked up to.
2013 Ford F-350 SD Diesel, 4X4, Crew Cab, Lariat
Sabre 2014 32RCTS, Pullrite Superglide 2900 18K