Hi!
1. Your radar probably is working it just doesn't always show properly. It's annoying when you don't see the arm sweeping all the time on the PPI screen inside the sub, but if you look up at your periscope shears and you can see the radar masthead rotating that means it's working.
2. Unlike U-Boats, an American sub's sonar heads are located on the underside the sub's hull. That means you can pick up sound contacts on the surface if you're close enough. Score one for fleet boats.
3. You likely have a deceased crew member. A burial at sea is in order.