How to Replace the Comfort Access Battery on a BMW 535XI


1. Turn the comfort access key over to view its backside. On the top edge, near the key chain loop, you'll see a series of ridges. This is the manual key release button. Push it and pull the top edge of the key outward to remove the manual key. Set the manual key to the side.
2. Pry off the top-rear cover using your fingernail or a screwdriver. The cover comes off easily. You'll now see the battery.
3. Lift the battery out of the comfort access key. Insert the new battery with the '+' side pointing up.
4. Push the cover back into place firmly to snap it on.
5. Push the manual key back into the comfort access key. Push it down firmly to attach it.