key batteries

[Lupin..the..3rd]

Got two E46 keys here, both with dead batteries. Seems they're of a sealed design, not user replaceable. BMW says buy new keys, at a few $hundred per. :roll:

Found this internet guy who does key surgery; he cuts the key open and does a battery transplant. Anyone ever used him? Seems a lot more cost effective than buying new keys.

http://www.bmwgm5.com/kr.htm

[John]

Not sure if e46 keys are the same, but I was able to replace the battery in one of my e53 keys as a DIY. It was pretty straight forward, but required a bit of soldering. I didn't have a soldering iron (or any soldering experience, actually), but lucky for me, I was working with another Dorki at the time who was able to help me out. Can't remember who it was, though. :roll: :p

Anyway, e53 DIY here: http://www.xoutpost.com/articles/x5/miscellaneous-x5/63324-replacing-battery-key-fob-e53.html

I think I even have a brand new battery left over from when I replaced mine, which you're welcome to if it'll work in your key... and you can find someone to solder it in for you.

EDIT: Are you sure the batteries are dead? Might try reprogramming to see if that helps. Again, not sure on the e46, but e53 procedure here: http://www.xoutpost.com/articles/x5/electronics-x5/9518-reprogramming-key-fob-bmw-x5.html

[HoodPin]

Shame on BMW for making such a stupid (though profit motivating...) design. :roll:

The guy you linked does seem to know his stuff. Seems like it would be worthwhile to try him first, before furking over alot more $$ to BMW.

[ausgeflippt951]

I would be genuinely surprised if the E53 key John posted is appreciably different from the E46 key. They all run off of a battery and I guarantee they're constructed identically. You may need to get the key reprogrammed after battery replacement, but it looks like the guy in the E53 link didn't even need to go that far.

So, I say pull the sucker apart, desolder the battery, and slap the new one back in there.

[Lupin..the..3rd]

Anyway, e53 DIY here: http://www.xoutpost.com/articles/x5/miscellaneous-x5/63324-replacing-battery-key-fob-e53.html
Looks identical to E46.


EDIT: Are you sure the batteries are dead? Might try reprogramming to see if that helps.
Yeah I read about folks doing this "reprogramming" procedure. I'll give it a shot. Although this is a 2004, which makes these batteries 9 years old at this point, so I'm not too hopeful.

[B r i a n]

I always thought the BMW keys recharged when in the ignition?
Did you try leaving in the ignition over night (assuming a secure location).

[APKhaos]

E46 DIY here - http://forum.e46fanatics.com/showthread.php?t=451510&highlight=key+battery

Battery source here - http://www.batterybob.com/product.asp?intProdID=309012

[magnetic1]

Id try reprogramming first. Mine are from 2003 and still work fine.

I too read somewhere that they charge when in ignition...

[APKhaos]

Yes, they recharge when the key is in the ignition but the batteries can die and/or develop sketchy connections that need re-soldering. Best bet may be to buy new replacement shell and blade and a battery, get it cut to match your original, then do the transplant surgery to move the RFID and remote transmitter into the new shell.

Seems that every bloody car in our fleet requires a process like this to replace a key [vs shell out silly money to the dealer] Its the challenge, really.

[SRG]

We just had http://www.bmwgm5.com/kr.htm repair a non functioning E46 key. Followed his instructions and a few days later the key was mailed back to us. Did the sync thing and the key has been working perfectly ever since. $60 bucks well spent. I going to send him our other non functioning key too. The dealer quote I got was $200 for a new key.

[B r i a n]

One of my keys died (wife's - from non use) on our 05 X3. I ordered a new battery a couple of days ago and took apart the key. I will follow up when the battery arrives and if there is a problem soldering back in and it working. Looked pretty straight forward - old battery came out relatively easy, just need to be slow & steady.