luvlabs is correct. Most satellite dish receivers are set up to work off of the "component" wiring. (I recently had the Direct service guy out on a problem and he wanted to change my set up from HDMI to component. But HDMI gives me a far superior picture.). If the audio jack is plugged in correctly, you won't get any sound.
Bob & Joan Alexander, 2010 Tiffin Phaeton 36 QSH, 2013 Jeep Wrangler (toad)
Lobo & Juniper (woof, woof)