Originally Posted by cjtamu

If you bypass the power switch and wire direct to the motor, then press down on the box, does it work? If it does, probably a bad switch. You can get one that will work at the auto parts store. If the pressure switch (the part you push down) doesn't work even when the power switch is bypassed, try this:

Loosen the screws that hold the box lid in place and lift the lid and look inside. You should see 2 posts attached to the pressure switch with a piece of metal on the end of the posts. When you push down, they make contact with the metal pieces below them. I've had several get bent from use and stop making contact. Push the pressure switch down and see if they make contact. If they don't, bend the lower pieces back up until they do when you depress the switch. Also a good time to make sure you don't have a loose wire somewhere.