2002: Keyless entry remote doesn't work (not battery)
 

Hi,
Suddenly my remote key stopped working (Hyundai elantra 2002) . I tried to replace the battery, but it didn't resolve the issue. Apparently it is not the battery.

1. When I press the buttons, it doesn't open.
2. When I open the remote to replace the battery, the LED blinks and the car locks. ie, only in some odd position while I am opening/closing the upper/lower lids of the remote, the remote works (without any button presses), but just to lock the car.
3. When I open the remote, I could take off the rubber (should there be some glue beneath the button to the circuit board?)
4. The above odd position could also mean that, when the circuit is being powered, the first default action is to send a lock signal??

Any ideas?
What would it cost to replace this?

Thanks.