Re: Defogger flaking out...

[desousa@cisco.com]

> Date: 12 Jan 1993 17:54:41 U
> From: "lis" <lis@at-mail-server.vitro.com>
> 
> I've got an '85 5000S with a very strange problem. The windshield defogger only
> seems to work at low RPM's (MPH?). I'm not sure why this happens, but when I
> get over about 50 MPH the windows start fogging up immediately, and when my
> speed drops down they magically defog. Because it's acting like this, I can't
> tell if the compressor is kicking off at a certain RPM, or maybe the A/C clutch
> is slipping at progressively higher RPM's, or if it's something else entirely.
> 
> Any ideas - similar experiences?
> 
> Thanks in advance-
> 
> Larry Spector
> LIS@at-mail-server.vitro.com

Larry, here's a guess at it:

Warm air is used to defog.  As speed increases, if a vent was somehow
able to mix cold air from the outside into the warm air stream...?
 
Maybe one of the heater/vent controls are not working?

Carl DeSousa