AC clicking noise

[Bluebird]

Been taking truck for light duty a couple of days a week since mid March. Rig idled about 7 minutes while got kids ready, AC on Hi. We got in cold icy temp in regarding cab. Drove 10 miles to destination. Got back in truck 50 minutes later turned on AC clicking noise started. Switched off AC, then back on, noise returned, I revied up a little, noise disappeared, drove 10 miles home with AC on blowing cold. "What you think happened?" I rarely use AC because it functions well. Thank you to all who chimes in. Blessings, Patrick

 

[RSchwarzli]

Where is the clicking coming from? Under hood or the HVAC box?

 

[Bluebird]

Sound from under the hood. Ran 5 miles home on max AC, cool air as usual, no noises. Hmmmmm.
Thank you for responding, Patrick

 

[Fastback67]

I normally associate clicking sounds like this with a leaf, twig or other small piece of debris, that has found its way into the ventilation system and is now touching the fan blades.