汽車沒開暖氣和吹風，但一開車，就有熱風倒灌進來

汽車沒開暖氣和吹風，門窗緊閉，但一開車，就有熱風倒灌進來，這是咋回事啊？
另外，汽車啟動時，總是聽到嗡嗡聲，啟動好了，這種聲音就消失了。
謝謝點撥。

所有跟帖： 

• turn the temp selection knob to far left (cold)... -internuts- ♂ (47 bytes) () 09/19/2009 postreply 06:48:03

• Duct gate is not in proper position -biglow- ♂ (375 bytes) () 09/19/2009 postreply 07:35:29

• thanks. my car,,, -xwq97ud- ♂ (169 bytes) () 09/19/2009 postreply 09:46:37

• my camry has the same problem co ask -boarding- ♂ (0 bytes) () 09/19/2009 postreply 13:04:30