Replacing a car key fob battery is usually a simple task. But, sometimes, it takes know a small trick to open the fob, or even in more advanced cases, a soldering iron to solder in a new battery. That is rare though. Most car key fob batteries are simple coin, or CR, or “button” / “watch” batteries. The most common car fob battery is the ubiquitous CR-2032.
I created a video showing the most common key fob batteries for each major car manufacture:
But I will be adding individual car brand guides here as well.
Major Car Brands DIY Battery Replacement Guides
 Acura |  BMW |
 Buick |  Chevy |
 Chrysler |  Honda |
 Dodge |  Ford |
 Hyundai |  Jeep |
 Kia |  Mazda |
 Subaru |  Toyota |