you must connect the CAN H and L wires inorder to control any function of the tv tuner. if those are connected and you still dont see any menus. if the tv tuner is set for another tv standard you may have to set it up blindly.
hit the right knob
click clockwise 2 times on the knob
now you should be in the tv standard setup, so just turn the knob until you see some snow/signal on the screen. once you come to the correct tv standard you will see a menu. if u make a mistake during the process, hit return a few times then start over.
this happened to a friend's and i had to set it up blindly. goodluck