Screen goes black. when we hook up my sons DVD in our vehicle it will play for about 2 min. then

Question

when we hook up my sons DVD in our vehicle it will play for about 2 min. then the screen goes black, its worked fine up till now, although we haven't used it in a few months. If I hold the mode button down it will come back on, but then after a few minutes it goes black again? I wish I had of hooked it up earlier because we leave on holidays soon. (help) Kerry