What temp do fans turn on? Don't think mine work

it's on a 2000 malibu with the 3100 engine. Today while idling it started to puke coolant out but I don't feel it was really hot. It was just above the half way mark. I found that the cap is broke so it's letting the coolant pass by the cap and go out the overflow tube. But I can't seem to get the fans to turn on. The only way is to put it on defrost or turn on the ac. I have a scanning software for my LS1 cars so I hooked it up to the malibu and watched the temp. It got up to 224 and still no fans. I've checked all the fused and all the relays and they are good. What temp do the fans turn on? also will not having any pressure in the cooling system make the fans not come on? Since my cap is broke it has no pressure.

Service manual says when engine coolant temp exceeds 223 degf- so you are real close- fix the cap- and try again...the fans work- since they come on with a/c-- so try again- put a blanket over the grille to get hotter quicker- but watch the temp gauge....