[WhoDat]

Originally Posted by villagetinker

If you do not mind going up a ladder, there is a little rod on the top of the sensor, if you push on it you should hear or feel a click, if not is is probably bad. These are under warranty, contact Hunter for a free replacement. The wire is typically in a conduit back to the controller. If go in to garage, where the controller is you should find a small white cable with 2 wires, you can disconnect (take a photo for future reference), try on a string, then go outside, remove the cover plate and pull the wire out, tie off the string, remove the sensor and send to Hunter, they will supply the address and RMA number. In about 10 days you will have a new sensor.
NOTE: you cannot use a MiniClick sensor on a Pro C solar sensor system. MiniClicks are around $40 locally, and Solar Sensors around $100 locally.
Ours failed after about 3 years.
Hope this helps.
PS, I have a miniclick for sale if anyone is interested.

Thanks villagetinker. The rod seems to be stuck in the down position flush with the top. Looks like it has a cover on it but I didn't want to pry it off.