We've changed the key fob battery before but now that the battery is dead again, I can't open the fob. Tried loosening with a thin blade, took it to a watch repair place but no luck. Can't get the plate off to change the battery. Any suggestions? Thanks!
Welcome to PriusChat !! The fob cover is actually stuck ? 2004-9 Prius Keyfob Battery Change or Toyota Prius: How to Change the Key FOB Battery - PriusDIY.com
Seems like having a functional fob is fairly important, best to keep working on it until it opens up. Since you mentioned attempting to using a thin blade, I will assume that you've already watched the youtube video. If you get stuck (or break the case), below is an instructable on case replacement. Cases can be bought online for $8-10 (give or take). DIY Toyota Prius Key Fob: 3 Steps Don't throw away the old case until you're quite sure the new fob works as intended edit: forgot to include the link, doh.
To remove the key portion, the small lever must be pulled to the side. This small lever must also be pulled to the side in order to slide the back off. Just wanted to ensure that was clear, as some instructions aren't very specific about it. From another thread: Make sure the manual key is removed. Hold your right hand in front of you with palm up. Place the FOB near the middle of your 4 fingers with the buttons down and the raised lip (on the back of the FOB) away from you. Place your right thumb on the fob Toyota symbol (the center of the back) Use your left thumbnail to move and hold the slide release button completely to the right Using your right thumb, push firmly toward the raised lip (away from you). The back of the FOB should slide off.