We have a Hunter ceiling fan with a remote control, that appears to be possessed. It occasionally turns on or off by itself. What could cause this... interference from a neighbors remote?

another device is interferring with it, just change the frequency of the fan. go to www..ceiling-fans-n-more.com/c...e-controls.php this site should help.

See my post below: (Sorry, we're in the same boat)

Hunter ceiling fan with remote, have 5, 4 are seriously impaired! Lights dim to half strengh after variable time 10 seconds-30 minutes. And lights or fan turns on randomly (come home & fan on full blast), and one in which the lights won't dim (just blinks when try to dim)! Hunter "kinda" admits there is serious problem with remote but doesn't have a solution. Tells people to try changing to different code due to possible interference (pain in **** to change code on ceiling base!), was totally ineffective. Then replaced receiver in ceiling base (another total pain) in 3 fans with new ones sent Hunter, still totally useless. Hunter's suggestion, don't use the remote, just use the pull chain. If I had wanted a pull chain fan, I'd have bought a pull chain fan. TOTALLY USELESS! Moral of story: If you want a remote ceiling fan (my friend found out that all their remotes are made by the same company in Taiwan), don't buy Hunter!!!!! P.S. I found a "Kinda"- fix for the lights dimming to half strenth. After turning on the lights, wait 1 second, then dim lights slightly, they will then stay on the strength that you dim them to. - P.P.S. When I changed the receiver in the one where the lights won't dim, it "solved" that problem...Now it has the same problem as the others, lights or fan turn on randomly!

change the frequency on both so they are not the same they have to be changed in the fan transmitter and receiver

This might be a silly question but have you tried takeing the batteries out of the remote?

I just installed a 2nd hunter fan model 23811 that also seems to be controlled by grimlins. If the power is left on, the light and fan randomly turn on and off. And no, it is not due to fans being on the same frequency. It appears to be an issue with the control module. I'm contacting Hunter.

Yes. Try resetting the code.

You will most likely need to replace the receiver with a new one from hunter. The receiver is actually a complete controller and contains the receiver, relays (which you hear clicking) and starting condensors(large capacitors which hold a charge that is "dumped" over the windings to get the motor to start from a dead stop). These appear to be pretty tightly assembled unless you have a desire to start replacing parts "off the board."

It could be that a neighbor has a ceiling fan with the same CODE that yours is set at. It does actually occur.
Try setting the REMOTE(Transmitter) AND the RECEIVER, located tucked in among the electrical wiring inside the CANOPY which is also called the 'Hanger Bracket', to a different but SAME CODE for each device. The RECEIVER, which will have four 'dip switches', as does the REMOTE, will be a small rectangular box with a short antenna from one end.
Good luck. :)

Many times this is caused by stray frequencies in the neighborhood. And, sometimes changing the frequencies on the remote and receiver reduce the occurrence.

But it sounds like this may not be the case, here. If not, the receiver in the fan is the culprit and should be replaced. No danger, just annoying.