How to find out why half of a sprinkler run does not work?

[18 inch Crappie]

Fired up my inground sprinkler system last week because of the lack of rain and brown grass. All is fine but one zone, it has 5 heads on it. It y's, 3 heads on one y and 2 on the other. The side with 2 runs fine. The side with 3 heads nothing. I was thinking ice but after running the zone a couple times over the past week and temps in the 70's it should have melted and worked ok. Tried it again today and still nothing. It sounds like something is pluged that side but is there something I may over looked before It tare up my yard?

[hotrod1]

Maybe the 3 heads are plugged? You could dig up a head, unscrew the guts from the sprinkler body and turn the zone on to see if anything comes out. Just make sure you have it dug up nice so you don't wash dirt into the head.

[18 inch Crappie]

Found the problem by having the zone on and I walked right onto it and got my shoe wet. Dug up the wet spot and found something cracked or came apart. Just waiting for the water to seep into the ground so I can dig and investigate.