There is a magnetic switch in the bay for the entire slide that indicates the slide is in and can lock. Since the front lock engaged I would think that it is adjusted and working properly. There is also an I individual magnetic switch on and right behind each lock. That is where I'd look. I have gotten mine to work by tapping it with the handle of a heavy buyer knife when one was causing problems. Mine was replaced and now working good.
Howard,Connie,& Bella,
One spoiled schnauzer
2007 Newmar KSDP
4dr Jeep Wrangler