I have got water into my remote fob a few months back, it still works but drains the battery v v v b quickly.

And hints on how to fix, or how to get a replacement one

You tried wd40? Or those packs dessicnt crystals you get in when buying things they want to keep moisture out of?

If you have a spare you could order a new battery, open it up, let it dry then fit new battery? Here's a post that'll help: Click

 

If you need a new key this post will be handy: Click

 

Kind regards,

 

Bob

Obviously after all this time it will be dry now, so corrosion / residue has probably caused partial shorts in the electronics. I've never taken one apart but if you can get to the electronics then you clean up the circuit board with some pure alcohol or at a push WD40, carefully with a cotton bud theres a good chance of fixing it.

An ordinary rubber is quite good at removing light oxidation from circuit boards.  Should your problem be cross tracking.

Not all electronic devices are sealed so it could be degradation inside a component. Or even water which can't get out.

it's rare a remote will recover to full working order from water damage no matter how long you let it dry out. More often than not something on the PCB has been shorted & no amount of drying out will rectify it