My key battery died, so I followed the manual instructions to start my car with the mechanical key. I removed the cap on the door handle which covers the keyhole, but I cannot get it back on now. I've tried every way, and the cap just will not stay on. I know this sounds dumb, but is there any trick to get it back on? I've been driving around with the exposed keyhole for weeks, and I've tried several times to put the cap on. It just will not snap in place.