I will adjust the voltage to the Mega and give that a shot... I had not thought about this. Thanks...
I am using the relay module in my attempt to keep as many PWM pins open for future expansion or features on the ROV. Currently, based on the value of the PPM input from the RC receiver, the functions either turn on or off the corresponding relay to send the arduino PWM signal to the appropriate L_Enable or R_Enable pin on the motor control. This allows me to use only 1 PWM pin to control the direction and speed of a given motor.