Tachchen people. Have a little problem with the climate at Buick. Since the Buick is in D, the climate no longer works. Have had it refilled now, and the pipes become really cold again, but the (I think that means) expansion valve does not open. Up to the valve the pipe gets really cold, and ́runs right. But after that is layer in the shaft. Is the valve kaput, or something else? How exactly does this valve work? 2 small pipes go I think they’re supposed to switch the valve.