[Derek Bessette]

Sounds like it's time for a little process of elimination.

Step 1:
Swap joysticks from port 1 to port 2. If motors on the other side start working then you have a faulty joystick. If you have the same problem then proceed to step 2.

Step 2: Swap the pwm wire from pwm1 to pwm 2 on the robot controller. If the other side starts working then you have a programming or hardware problem with your robot controller. If you have the same problem then proceed to step 3.

Step 3: Swap the motor output wires from the two Victors. If the other side starts working then you have a Victor problem. If nothing changes then proceed to step 4.

Step 4: Swap the motor leads from the two motors. If the other side starts working then you have a wiring or connection problem. If the nothing changes then I would try a new motor and check that the wheels can be turned by hand (not locked mechanically).

A lot of these steps can be checked with a multimeter as well.

Hope this helps!