Steps on how to replace the battery on your key fob.
1) Open the Key
2) Using a very small screwdriver, press down on the small tab and at same time pull the key end out.
3) Pry the screw driver up at both holes/slots as shown slowly, bit by bit.
4) Now the battery is exposed and part # is written there!
5) Pry up battery where shown in diagram. On the casing it says to push down from left side in a bit, but it didn't work for me.
6) Replace battery with new one. Mine was a CR1620. Notice on outside of battery pack it just says 1620, but if you look at battery it does say CR1620. 3 volts. I bought mine from Canadian Tire, on sale for $3.99 ea, $1 off! (Canadian).
7) Line up back where key ring is and push down using both hands at all corners until click sounds are heard
8) Slide back in the key end and it should click
9) Good for another 3-4 years for each (I used 1 for 3-4 years, then used other for 3-4 years on my 2006 Mazda 6) but i don't drive every day!

 

Good to know about this process....