I've got a 2000 Merc Sable -26K miles. Car is great but the the front defrost comes on HOT for no reason. the only way to shut it off is hitting the off button or even somtimes turning the AC on??

anyone have any ideas on how to fix this or should I jsut go to the manual climate controls. that is replace the entire radio console?[img]smileys/smiley7.gif[/img]

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When on auto, the system will wait until the coolant is hot enough so that it can blow whatever temp you have previously selected. It will continue to blow until the cabin reaches the desired temp you,ve selected. Then it will either shut off or more likely lower itself to a much lower fan speed setting. Then speed up again if the cabin goes below the desired temp. One word of advice, use the defroster manually until your winshield is clear, then switch it to heat or vent on auto and your desired temp. The defroster uses the A/C system's evaporator, condensor, and most of all the compressor. It's a huge waste of gas. (unless ofcourse you are in a blizzard and then the defroster on high is a great help) Good luck!

well, let's try this again. relooking at my post I guess I didn't xplain myself real well.


this problem only happens when it is hot (warmer) outside. it alsoseems tohappen when the windows are rolled down.heat blows out of thefront defroster for noreason andat times I can't shut it off. also the radio will lock up when this happens (can't switch channels or turn volume down).


I can't help but thinking this has to do with the auto climate control. it also Never happens when it is colder outside!! so any ideas??