Jeep Grand Cherokee key fob battery

Separate remote fob

1. The remote is a small standalone unit. You will not need to touch the ignition key at all.
2. Look for a screw on the back or a notch on the edge. Remove the screw if present, then twist a coin in the notch to split the case.
3. Lift the old coin cell out and press the new one in with matching orientation.
4. Snap the case shut and watch for the lights to flash when you press lock at the car.

This key takes two CR2016 cells. Change both at the same time and stack them the way the old pair sat; mixing a fresh cell with a tired one shortens the life of the new one.

Key with remote in the head

1. The remote electronics sit in the plastic head of the key itself, so there is no separate fob to open.
2. Find the seam around the head. Twist a coin or small flat screwdriver in the notch at the blade end or side until the halves part.
3. Replace the cell with the same face showing, and make sure the rubber keypad sits flat before closing.
4. Press the head together until it clicks and test the buttons. The transponder chip that lets the car start is separate from the battery, so starting should not change.

A CR2032 is 20 mm across and 3.2 mm thick. CR2032, CR2025 and CR2016 share the same width but not the same thickness, so a swap between them can leave a loose contact or a case that will not close.

Smart key (push-button start)

1. Most push-button fobs hide a metal backup key. Press or slide its catch and draw the key out first.
2. Use the slot where the metal key sat. Twist, do not lever hard, and work along the seam until the halves separate.
3. Note which side of the old coin cell faces up (usually the side with the writing), lift it out with a plastic tool, and press the new one in the same way.
4. Reassemble, refit the emergency key, and check that the car sees the fob when you press start.

A CR2032 is 20 mm across and 3.2 mm thick. CR2032, CR2025 and CR2016 share the same width but not the same thickness, so a swap between them can leave a loose contact or a case that will not close.

A CR2450 is 24.5 mm across and 5.0 mm thick, much fatter than a CR2032. A thinner cell will rattle and lose contact, so buy the exact size.