I have a 2002 S60 AWD 2.5T

Lately, whenever I stop at a light or stop sign the fuel needle will drastically drop to empty. As it does, the gas light some times doesn't even turn on. On top of that, my rear doors do not unlock majority of the time when I press the unlock button. But wait! There's more!
My trunk doesn't open unless you manually unlock it with the key. And today my fuel hatch wasn't unlocking.

Someone please help me. Is it something I would have to replace such as a fuse? Or would I need to reprogram my car altogether? (I recently changed my battery)

 

Not a forum issue, that's for sure.

I'd have to check the diagrams, but I think all that stuff runs through the REM. Might have a REM going bad. It isn't a fuse.