Hi when 12v power is applied, I want a 12v relay to ON for 2 seconds and then off even when 12v power is not cut off.

 

You posted in the wrong section but I'm sure a Mod will be along to move this post. A 555 timer circuit will probably be the way forward. See this thread for a starter

 

Hi when 12v power is applied, I want a 12v relay to ON for 2 seconds and then off even when 12v power is not cut off.

Link to an alternative to using a 555