The control surfaces are the ailerons, elevator, and rudder.
An inexpensive, 9 bucks, loaded meter is
http://www3.towerhobbies.com/cgi-bin...?&I=LXWDZ5&P=0 plus you’ll need the leads
http://www3.towerhobbies.com/cgi-bin...?&I=LXL332&P=M
The transmitter does not appear to have a voltage indicator so you’ll need to test it also.