what can i add to EASYCAST resin to make it harder when dry?
Low current. Might have a pinched wire where some if the internal wire threads are severed and not enough current is making it to the lock solenoid or window motor. You'll have to look inside the door jam to inspect the wires inside the rubber boot. Or, corrosion inside the door might have corroded the connection(s) to the lock and window motor. Good Luck!