T680 Radio replacement - Reception problems

[Golfnut]

I replaced the factory radio on my 2014 T680 last week with a Jensen 1635BT unit so I could have bluetooth for both calling and streaming. I didn't not have to use any adapter harnesses. Everything plugged in fine with the exception of a single connector on the truck side that has a blue wire going into it. There is also an unused blue wire on the head unit that is to power an external amplifier. I did not use it. The bluetooth works perfectly fine but I get horrible FM reception and absolutely no AM reception. Where did I go wrong?