Originally Posted by pewtewr01
I have quite a bit of experience with these trucks and the audio systems in them...I can probably help out.
From your description it sounds like the previous poster was on the right track. The radios and navigation systems these trucks came with had internal amplifiers. However the navigation systems out of 09 or newer trucks used external amplifiers. They are not a direct plug-n-play match with your truck. If you have one of these newer navs, you will need to get the amlifier and "T" harness that allows it to be connected. There are also a few other parts that would be required but I will wait to go into that until we are sure that is actually the problem.
So to determine what type of navigation you have, can you tell me the part number of the top of the unit. Should have four digits (letters and\or numbers) followed by 18k931. If you can tell me the first four digits I can tell what type of radio it is.