check your brakes and brake fluid level. When the brakes were low on my '94 Silverado, and almost all the fluid was in the calipers, it did the exact same thing.
+1 that would be my first thing to check.i pretty sure that there is not a sensor to sort of speak there is a switch i believe. i could be at the top of the e brake lever where it is mounted, that would be my guess. Ill ask people around my area and see if they have any suggestions. Nothing else you could always bring it somewhere and ask.