From your code
for(int pulseLength = 0; pulseLength < 100; pulseLength++)//rotate towards the brush
From the example for the library
#define SERVOMIN 150 // this is the 'minimum' pulse length count (out of 4096)
#define SERVOMAX 600 // this is the 'maximum' pulse length count (out of 4096)
for (uint16_t pulselen = SERVOMIN; pulselen < SERVOMAX; pulselen++)
I would conclude that the pulse length never gets long enough in your code to make the servos run. Change the range of the for loop so that its starts at 150 and ends at 600 and report back.