If it is the mat stat the red power light should be in all the time and the green heat light should come on when it is powering the mat and if it is a pulse stat the red light flashes (pulses) to show power going to the mat.
As Donnie says if its constantly pulsing on an off its a pulse. If its on for a few minutes an off for a few then its a mat. If for some reason uve ended up with a dimming it will be anywhere from off to on full brilliance an anywhere in between.