[Kurizma]

This is for a friend of mine. He has a CRX and his car has a hard time starting. He's been having this problem for a while. I know it's kinda weird but when the weather's cool out and he parks in the shade, it'll start up just fine. But after driving it for a while or a day in the sun, it won't start. He turns the key and nothing happens. He only gets a single click that seems to come from behind the steering column. We've replaced the Starter, and the Ignition coil and still the same problem. Anyone have any ideas?