wpwarren

I am guessing it must be a switch problem, but I noticed recently that whenever the heat is on I hear the electric fan running. After closer inspection I realized that not only is the e fan on, the ac compressor is intermediately engaging and disengaging. I then turned on the ac and noticed that when the ac is on it is only intermediately on. The clutch engages, then the efan turns on. This happens exactly the same whether on ac or heat, with hot or cold air. This is my first winter with this jeep so I wouldn't know if this was a problem last year or not. The vehicle is a 1999 jeep cherokee se if that helps.

wpwarren

I guess a follow up question would be what causes the e fan to kick on. Is it a signal from the switch or from the compressor somehow. This may or may not help me figure out the problem.

Bustedback

The A/C will come on with the defrost mode to help dehumidify the air and clear the windshield faster. The efan kicks on any time the A/C compressor is on in order to keep the condensor pressure in check. The efan will also come on when the engine coolant temp reached between 217 and 220 degrees.

djb383

Any of the 5 vent selector positions (circled in yellow) engages the a/c compressor. Heat can be added (temp selector toward red) regardless of where the vent selector is set.

wpwarren

I didn't even think of that as a possiblility. All of my recent vehicles have been from the 70's and didn't have that advanced of technology. Thanks guys.