Fix the can light and see if that cures the problem. Sounds like the arc fault breaker is doing its job.

Thanks...I did kinda feel the can was the problem..however, I was able to open the circuit box and redid all the connectors, seemed the blk wire was loose, but that did not fix it. Could it be a faulty thermal protector? I guess I can cut that out of the circuit and wire nut it, as my next attempt. But I'm thinking a pinched wire and a fixture by fixture elimination process in the attic..it's a low hip roof and I think I'll just about fit..any other suggestions before I commit to that torture? Thanks in advance...

When you are through with that wirenutting trick you could go cut the brake lines on your car too.

topcat162, if you bypass the thermal protector for testing, please don't leave your bypass in there permanently. If it turns out to be the problem, disconnect it and leave it until you can obtain a proper protector for replacement.

If you are going up there take the complete can light out of the circuit. It doesn't work anyway so nothing is lost.

Remove the lamp from the fixture and look in the cavity. The access method to the junction box should be obvious. Attic trip unnecessary.

Thanks y'all...yes, I can drop each can and access the junction box to isolate the bad can from below, I will try to bypass the bad can thermal protector, n' if it works, will put in new can, also will try to isolate fan and closet light at switches first to test those circuits anyway. Thanks to all. Brake line, really!

If you do the brake line thing please invite groundrod for a ride- I think he needs some excitement in his life.