AC dies after driving for a while.

[mrplow]

I have a 1998 Ford Explorer Sport. The AC works occasionally. It seems to work ok at night or when it's cool outside. It seems to hardly blow cold when it's hot outside and then, more often when it's hot, the air coming out goes completely hot. It's as if the compressor shuts off.

For example, when I left work yesterday, 95 degrees and humid, the AC was blowing slightly cooler air than outside. At stop lights I could hear the compressor kicking on and off. After about 10 mins the AC seemed to die and HOT air started blowing out. Then, at lights, I didn't hear the compressor kick on or off. It just idled normally. If I let the car sit with the AC off for a few hours the AC seems to come back, but it will do the same thing. Today, overcast and about 88 degrees. The AC blew slightly cool air, but it lasted 45mins or so before it started blowing hot air.

Any ideas why the compressor seems to stop working and why it happens more frequently on hotter/more humid days?

Thanks,
Peter

 

[Eagle Eye]

Check the ac lines at the drier and see if they are freezing up and forming ice on the lines. If so it could be a little low of freon

 

[rhauf]

also it may be a failing low pressure cycling switch (i had that switch fail, gave similar problems). be sure it's fully charged too of course.