Like the title says my a/c pump constantly runs.. not like 100% but is cycles on and off.. on for 30 sec or so off for 30 sec.. even when the temp selector is all the way in heat... the ONLY way i can get it to stay off is by removing the fuse.. heat works great and a/c works great... but the problem is the pump wont shut off and its most likly killing my gas milage.. ANYONE have an ideas??
its a 98 D 4x4 with a 5.9

 

What mode are you in? The only modes where thecompressor will not run is Vent and Floor heating. All other modes will use thecompressor. The last few modes where thecompressor comes on when youare in heat mode is to remove the humidity buildup within the cabin to prevent the windows from fogging up

 

Like Kensai stated: the a/c compressor will operate in any of the a/c settings or any of the defrost settings regardless of where the temp setting is set at. A/C is for air conditioning not just air cooling. That is why it will run in the defrost settings, so that it will remove the humidity. Hope this helps. If it is running only in these settings it is running the way it is suppose to.

 

AWSOME... my truck is doing what its saposed to do then.. thanks guys..