2000 Diamond Edition Jimmy

My passenger headlight goes off on me after a short period of time I turn the headlights off then back on and it comes on for a little bit then goes off again I changed the switch and drove all over and it diddnt turn off until I pulled in my driveway smallest bump ever! It shut off I parked it and shut the vehicle off I turned the lights on and the passanger headlight shut off I turned them off and back on again and it still did it could the headlight be be overheating? Could it be the lowbeam relay? Its the only light not working properly I priced the headlight and its expensive for the ballast and the bulb but it doesnt seem to be the balast or the light if its a ground where do I start troubleshooting with this kind of light? Thank you>>I should prolly add that it has done this before then stopped for about 2 months now its doing it again can anyone help with some solutions or can anyone tell me if they had the same problem? I know its real bright when it stays on its not dimming or anything it just shuts off until I turn the switch off and back on again also it will shut off sitting still with out driving it or hitting any bumps anymore help would be nice thanks for all your help guys I am flustered and stumped!