Does anyone know how to turn off the "tamper" switch on this device?
Maybe a small piece of electrical tape or dab of crazy glue on the tamper switch to keep it in the closed position even when the cover is removed?
Shouldn't it turn off when the cover is on?
Yeah, there should be a little piece of plastic on the inside of the cover that makes contact with the tamper switch to push it closed when the cover is in place.
It sounds like either the piece designed to depress the tamper switch has broken off or the switch itself is bad. Check to make certain that you did not replace the cover incorrectly. The stud on the cover should be immediately over the tamper switch when the cover is replaced.