Brand new and sound in left ear only - Beats By Dr Dre Beats By Dre Detox

Make sure that you have a stereo plug on the microphone to be able to get both channels.

this is an oxmoron you cant have checked every thing

left and right ear audio on CBs come from a common mono signal

so the right ear signal is missing or the headphone on the right ear piece is busted

sherlock....

Try cleaning ear probe tip with alcohol. This sounds like the oil' earwax on the sensor routine.

get new earphones those are cheap or you can adjust the head phone volume in the ipod or iphone in setings

Ok so it sounds (no pun intended) like either the L speaker itself is blown or the solder connection has become broken for the left side. So you can either try to fix them or if possible replace with a new pair. You can get a very good set of ear buds for for reasonable price at...TJ Max. Yes no joke I bought mine there at they are great and they were only 7.99 but dont let the price fool you, they are of HD quality and brand.

Try updating the firmware.

http://kb.sandisk.com/app/answers/detail/a_id/156/kw/firmware/r_id/101834

Try it in another pc, you will see (or more precisely not hear) the most likely fact that the headphone's cable has quit. Buy a new pair.

I have this problem all the time with my JVC earbuds. This may sound a little gross but it will work. I put the ear phone in my mouth and **** on the end of it pretty hard. What I have found is that sweat or even wax will plug the little hole and prevent the sound from coming out.