♣Zen31ZR♣ said:Yeah, that's pretty typical on Z31s. Basically it defaults to the defrost setting, which blows up on the windshield. After vacuum is reestablished, it will blow properly at the last setting. Basically means you have some bad vacuum lines or check valves, it'll only hold vacuum for a few seconds. The only fix is to trace all vacuum lines going into the climate control, hopefully you can find the one that's leaking without tearing the dash apart. If you have to tear the dash apart, it's up to you, but you might just want to live with it.