2004 F150 Lariat with 170k - My fan (and heated seats) turn on for a second or two and then off for a few seconds. This repeats. All other electrical components in truck work fine. Battery and alternator test fine. There is also a strange noise under the dash. Almost like an electric motor cycling. Happens whether driving or in park. I disconnected the battery and reconnected. It seems to have gone away for now... Ideas?

 

Welcome are you talking about the AC/Heat Fan blower? The clicking could be the blend door. Disconnecting the battery could have reset the system back to normal, for the time being.