But logic dictates, that if it worked fine before you started, it must be a result of having the radio out.

Could that truck have a 2nd fuse panel that is being overlooked?

If nothing is working (except the fan), could you have disconnected the HVAC ground?

Does the radio fit easily, or do you need to push it in?

Is there any change when the radio is out?

Sorry, just rambling thoughts while typing.