I spent some time reading posts and searching for an answer to a question (see below). I liked what I read and decided to join. By way of introdution: I am the son of a retired mechanic and grew up with wrenches as play toys. Dad is now 90, a WWII veteran, married for 70 years (celebrated this week the 70th) and is still my main advisor on mechanical issues. His data base is lacking when it comes to anything computer related. I am a Vietnam veteran and after the service went to graduate school in chemistry. I'm in my 37th year as a univerity Professor of Chemistry.

The question that brought me to the forum is: On the drive (450 miles)back from visiting my parents, I noticed that my AC was cutting out. My Ranger is a 1997 XLT, 4 cylinder, 5 speed manual. I played with the controls and found the cutting out happened everytime I was driving up a long grade. Blower on high would cut off. Once a reached the peak of the grade and started down, blower would come back on. I switched the AC and in the vent position, I observed the same symptoms. Is this normal? If so, I assume there must be a vacuum activated cut out switch. This would make sense in the AC mode but why also in the vent mode.
Or, Is this a symptom of a problem?

I bought the truck new in 1998 and it has about 105k miles. I normally don't drive it on long trips but I don't recall seeing this behavior previously.

 

At WOT (wide open throttle) the PCM will disengage the A/C compressor .
You may need to check the throttle position sensor.

 

Thanks for the reply and I suspected there was a link to WOT and the compressor. I wasn't at WOT - highway speed was 60-70 mph and it seemed to only effect the blower as cool air was coming out. But the blower also cut off in the upper vent mode where I assume the compressor was off anyway.