Arduino to act as a switch for a remote
Get your multimeter and find out how the switches are connected and if they are pull up or pull down. Also measure the voltage. So if a switch does a pull up to 5V you can just connect your arduino and output a HIGH. If its a 12V signal or sth that isn't supported by the arduino make the arduino turn on a transistor which then switches 12V to the  switch. Vice versa for a pull down.