weak motor problem

[stefanosdimos]

hallo

its been a while time i m trying to rebuilt the sim !!
i m using arduino uno r3
motomonster bridge clone(china) http://www.ebay.com/itm/ICSJ012A-Monste ... 339250be48
led power supply 12v 33 amp
the code from inside https://github.com/X-Sim/X-PID-Arduino- ... 62b6d81c1c
and 2 wiper motors
the sim is mooving ,but the one motor has no power,i cant stop it with my finger,and the pot its loosing its position all the time.i tried to change output from left to right,and right-right and all options but i have the same problem with the other motor,its or the left or the right weak.

thank you