: Idles strangely when turning heat/ blower switch "on"

06-23-10, 12:01 PM
Hi everybody,

My blower motor has apparently died again and when turning the heat/ac on the motor idles strangely, its behaving like a lawn mower that needs its "choke" adjusted. Earlier I found a gaping hole where my air cleaner housing connects to the throttle body (which would explain why the pcm was telling me that I had 3 bad oxygen sensors) so I taped it off as a temporary fix and the codes went away, but now I'm getting this weird idle problem when switching the heat to on even though the blower is now longer functioning. Anyone know the cause of this?

Also, the interior of my car gets really warm near the floor when my heat is never on, when I first got the car I never had this issue and I never really paid attention until a passenger asked me If I had the heat on which I did not.


06-23-10, 06:08 PM
Is any of the pre-2000 HVAC system (blend, diverter, temp doors) controlled by engine vacuum ? A leak in a line like that would cause rough idle and some part-throttle hesitation.

Many of these systems will keep the same temperature setting when turned OFF - the trick is to set the system to 60 degrees before you shut it down in the summer, or it will continue to sense the setting and try to maintain it with no blower running.

Some of this is in the owner's manualsand shop manuals but you have to dig for it.

06-23-10, 09:04 PM
Submariner I'm lost....I dont understand anything you just said. lol

06-23-10, 10:20 PM
What Sub is saying is that the '97 still had mode doors vacuum operated and you may have a vacuum leak. Does you parking brake release when you put the car in gear? The release is also vacuum operated and on the same vacuum circuit.

06-24-10, 10:52 AM
Thanks Submariner and Ranger, I found the hose connected to the throttle body that goes across the intake manifold wasn't pushed all the way in properly.