At idle... there's a distictive 'tick'... someplace under the hood. It's not constant... just 'tick'... then maybe 30 seconds later another 'tick'. I can't locate where it's comin' from and have never heard anything like that previously. No indications of anything amiss on the guages and runs fine.
Anyone else have this problem? 'Know what causes it?

 

I will hear my Air conditioning cycle on and off every once in a while.

My 99 explorer does not have a seperate ac on/off switch. It is "smart" and cycles it on and off as needed even in winter to defrost the windshield etc...

I wish there was a ac off position so I could override it other than turning the whole climate control off.

To see if this click is the AC cycling try setting your climate control to off and see if it goes away.