I just picked up a 2004 silverado. It is a 2500hd 6.0 truck and did not come with the keyless entry remote so I ordered one off line. I have tried a hundred times to get it to program and cannot get it to. Everytime I turn the ignition with the unlock held the doors cycle and the horn beeps, which doesnt happen in all of the videos. Did my truck come with keyless entry? Is there anyway to tell? Thanks in advanced!!