Depends if your truck had a sub to begin with or not. Having dug behind the dash on my '04 NO plug for the subwoofer behind the radio. There has to be 3 connectors in back of the radio to plug in a subwoofer. The sub connector is only 3 wires Enable, Sub+, Sub-.
I have not pulled the RR back panel to see if that connector is there. In '04 its connector
an 8 pin with 5 wires, Batt, Grnd, Enable, Sub+, Sub-
What I had planned on doing all along is grabbing some junkyard harness and cut the ends off so they are like ‘pig tails’ and just run my own wires from the radio to the sub.
Still trying to work out the replacement radio that will drive the sub and its been too cold to work outside.