My drivers side top light stopped working a while ago, the other day i replaced the bulb with the same halogen bulb and it worked. For 10 minutes.

Got home, turned the car off and turned the car back on again 15 mins later to go out and it stopped working again. Me and my mate did the replacement ourselves and couldn't work out what the problem was. Is my ballast stuffed?

We did NOT touch the glass on the bulb at all during replacement and everything was put back together properly, any advice would be great.