Ah yes the infamous main relay problem... many people have this problem and claim that hot weather helps...others swear by slapping the hell out of it... I would just replace it... but you are going to find that it is a honda dealership part and it's not going to be cheap...

You can find it behind the drivers side dash... It's a grey box bolted up behind the heater vent with a 10mm... if you have small hands, you can get it out without ripping your dash apart... I believe it's attached to a 14 pin connector, so make sure you unplug the right one...