Replacement Battery for Keys

Hi All

Does anybody know if you can replace the battery in the key fob on my 2004 X3. I only have the 1 key so i need to get the battery replaced on this fob because it isn't working at all even thought they are supposed to be recharging when in the ignition. Are they a sealed unit or do split to replace the battery

Sealed unit but the battery can be replaced. See video:

Nice, I recall another DIY series here a few years ago -- no video but still pix -- same thing except it required very light soldering as I recall. The battery was a Radio Shack thing for about $2.00 and epoxy was used to close the case. Still a pretty easy to save a couple hundred bucks! This video probably should go up in the "Pay it Forward" thread for future use too.

If you have bought a used BMW and have only been given one key that doesn't seem to work well, don't assume that just replacing the battery will fix it.

Others on this forum have found the following can also be factors:

- previous owner may have gone swimming with the key or laundered it (corroded internals)

- there may be a substance on the key shaft that prevents charging (clean with solvent)

- the receiver may need replacing on early X3s (some upgrades were done under warranty)

I don't think there too many on this forum that have had a key battery die that are original owners.
Even if you neglect to periodically charge an unused key, they seem to keep going and going.

So don't tear a key apart until you have ruled out other causes, possibly with the help of a locksmith who can test it and reprogram if needed.

Cheers All

I will try all the options before i open the key case up,

Cheers Again for all your suggestions