I have a 2006 Nissan 350Z, Having problems with tire indication light. Front shows info but Rear only shows one tire.....I have read manual and i still dont understand.

Light shows problem with psi. I have never owned a 350Z or a car with the
tire indication light.  My light shows
my tires are low. Front is fine but It shows only one Rear  amout..shows ----
. thats it. I dont understand. I did as one sight said 34 in both front and 37
in rears. still not registering . Only one rear shows amount.  I can not tell
which rear is messed up. Researching the rear tires I still dont understand
which one is messed up. I have increased air to 37 on all tires. Still one of
the rear tires is not showing up. Just get -----. Please help ! I dont know
which  rear tire is bad. From what I have read..It could be a sensor.. I even
took my car to Pep Boys and they let me know there was not a
problems...BUT my light is still onl! Help   !! never had a sensor on my tires
before.. Yes I dont understand! Much less know where the sensors are
located .
Please help ! Thanks to anyone with advise !!