Sub not working after installing the jensen vm9022...

Question

We installed the vm9022 Jensen radio deck into a 2003 Tiburon. The original radio was an Infinity premium sound system with amp and sub-woofer. After installing the new radio deck we are not getting sound out of the sub. We have cheked and rechecked the wiring and all seems correct. I am guessing that the amp is not getting enough power to turn it on. With the amp buried in behind the rear side panels it is hard to verify that the amp is getting powered on. If we put the old radio back in the sub works again. What do I need to do or check to get the sub to work again?