So after reading many threads on this, I finally figured out that my speaker was junk. (For those of you having a problem, start off by checking this, I've read and figured out this is one of the most common problems) So I've narrowed this much down, and now I know that speaker was junk. I used a small external speaker from a little alarm clock (even less than the $5 Radio Shack buzzer
Now I have to figure out why the buzzer just STAYS on when it's in reverse. The owner before me DID let a trailer hit the bumper right next to the sensor on the passenger side closest to the license plate.
Now I haven't had time enough to go through, blow off and clean all the sensor eyes, or go through and blow out/di-electric grease all the connections. So until tomorrow when I have time that is my next diagnostics.
One question I have is how do I "jump" those to check and see if that one sensor is bad, or can you not do that with these. And if you can and I figure out that the sensor is junk, how much do they run? I would love to have the rear sensors working because #1 its an option on the truck and #2 my wife drives the truck once and a while and is quite a bit different than her Xterra. Tomorrow I will post my findings after all the cleaning and lubing is done but in the mean time for my other questions if anyone has insight (which I'm sure there are plenty who do) I would greatly appriciate it!
Oh by the way it's a 2008.5 SE 4X4 with 18,226 miles