LXI series tv channel 4 issue

Our cable box uses channel 3 with no problem. My dvd player uses channel 4, big problem. I dont have the remote, however I have tried to auto scan channel and tried both on air and cable using the menu button on the front. I still cannot get the tv to change channel to use the dvd player. We had it set at one time and then I messed it up and am trying to get it back. I did a google search and tried the suggestions I found without success. Any help would be appreciated. I even have tried to use the universal remote from the cable box and can get it to turn on and off and volume control, still no luck with the channels. Thanks for the help Docfl