I had the same problems the day I bought my car, it was fine on the motorway, but when I hit traffic it overheated badly, had to pullover and let he cool down before attempting to get home. There were a couple of fuses that were blown, but I believe the most significant was the 50 fuse that sits in a bot near the battery - its a different kind of fuse and there are 4 of them in the little box. Not sure what the box is called, but once I changed that everything was working fine again.

Hope that made sense, and is of use to you!

Regards

AR