Former VWDieselParts.com Forum

How doed one repace the lock remote battery in the key of a 20003 TDi?
I can't see how to open it!

Pull the two halves apart longitudinally (lengthwise). Then using the actual key, put it in the slot that the key folds into and pry the two halves of that half of the key fob apart. Kind of hard to explain in words but it's pretty easy. Basically the key fob is in three pieces. One piece is half of the entire fob and is what the key is hinged into. The other half is where the battery resides (CR2032) and it splits into a top and bottom which can be popped apart by putting the key into the shallow depression where the key folds into then using that to pop the two battery section pieces apart. Hope this works for you. I know this works on my 2006 and I'm pretty sure the 2003 is the same fob

After prying apart the half with the blade from the half with the keyring. The part with the blade is just that.The part with the buttons is the electronics.The front has the 3 black buttons.This last part splits front and back.The front has all the buttons.The back cover just has just the 2032 cell and holder.

Exactly. Sounds like you were able to get the battery replaced then?

both remotss stopped working.
When I locked doors with inside button a second later they reopened.
Yesterday when I tried to start. battery was weak. Clock reset to 12:00 Trip odometer reset itself to 0.0. I put new CR2032 llithium cells i both key fobs in the last few months, and have worked fine until today!

I put new 2032's in the keys in August and October. Have worked fine until today

If your car's battery dipped a bit and reset your cluster you may have lost adaptation between the car's comfort module and your particular fob. There's lots of threads on TDIclub about how to sync 'em back up again...a "two key" method and a "using VCDS" method.