DIY....replacing battery in key fob....

[mrbmwx5]

1) Ok so here is my first "KEY DIY"attempt at a detailed also if you mess up your own key trying to do this don't yell at me!

So I have the 2 key fobs that came with my car when I bought it used. One I use everyday and the second one has had a dead battery since I got the car. When I called the dealership they wanted like $260.00 for a new one. I did a search around here and found you could get deals and what not and possibly get it down to around $90-120 bucks.. still way too much in my book since I already had a working key.

After talking to RICHIRICH who had taken apart a key fob . I decided what the hell the key was already dead anyways...

Here is the key before I tried anything..


2) I then proceeded to take a matt knife and xacto knife and basically carefully cut the key open along the seam where the top and bottom joined up.

3) Next I took a small chisel and broke the spot welds on the battery that connected it to the rest of the circuit board.



4) Once I had the battery out I looked at it and took the model number "a panasonic VL2020 3v" I found the exact same battery on ( VL Lithium Coin Cell Batteries 3V 20mAH 2 PIN VERT )Mouser Electronics - Electronic Component Distributor for $4.73. Once I got the battery is was a simple matter of soldering the new one in and making sure everything fit back together.


5) Before I glued it up I rubber banded the thing together and went out to my car to see if I could program it.

Put the working key in the ignition. Turn to position 2 for like 1 second then back and remove the key.

Press and hold the "unlock" button then press the "lock" button 3 times, you should hear all the locks cycle through.

Now take the non working key and press and hold the "unlock" button then press the "lock" button 3 times.

Then turn the ignition on and off again to end the programming....

I took the car for a drive to charge up the battery. Once I was certain it was all working I glued up the key again with some super glue....

Here is a pic of the key being glued.( I used liquid glue)



6) While definitely not a hard or complicated "DIY" project I did save myself about $200 and had fun while doing it...

[FSETH]

Thanks again, MacGyver...I mean mrbmwx5.

[Brit6]

Nice i did the same thing to the key that came with with my x5, but i just could not get over how used and ugly it looked, so i just replaced it with a new one

[dkl]

Excellent Job But be careful with soldering the battery for all those who wants to attempt this. If the battery gets too hot, it can explode on you...not a pretty site when you're only inches away from it. That's why the original battery was spot welded or tacked on.

[rayxi]

Nice work. Can't beat the cost!


dkl: looks like the new battery has pins welded on already so any soldering would be on the circuit board not the battery.

[chigga]

i did the same mod and fucked up my key... i guess my key was just really dead. ig ot a new battery and put it in and resoldered it, nothing happen. Maybe because i only have one key, since you need 2 keys to complete the programming.

[jayjay_dee]

good job once again Tom... you should be in the Xoutpost's "Hall of Fame"...

[dkl]

Originally Posted by rayxi

Nice work. Can't beat the cost!


dkl: looks like the new battery has pins welded on already so any soldering would be on the circuit board not the battery.

Agreed...but for an amature in soldering, if you leave the iron on the pin too long (the iron needs to touch the pin/circuit pad to solder properly), the heat from the iron can easily conduct to the battery in no time at all. Just be CAREFUL...that's all I'm saying.

[RMak]

Unfortunately I went the route of buying a new key when my key fob died. Paid $200 dollars for it. Hopefully when I do have some time on my hands, it wouldn't hurt to try to do this myself. Key is dead anyway, so it can't hurt. Thanks for the right up though...

[Mahmud5]

Thank you! That will save my dying key!