Im driving an 05 335 and recently the A/C started blowing hot air. It seemed like it would blow cold until the truck water temp got to a little over 200°. Then it started blowing hot air at about 190°. Now its at about 170°. Even though our company fleet is 100% Peterbilt my company uses the local KW dealer for service. I have had it in three times in the past month. The first time they replaced the condensor. Blew cold air for maybe a week. The second time they said that it was low on freon and topped it off. The third time they said the tech couldnt get it to blow hot air and didnt know what the problem was. (the tech test drove the truck during the night when its somewhat cool outside!) Any ideas on what the problem might be? I cant take this Texas heat!
Blend door operation or water control to the heater core. You could pinch off one of the heater hoses to the heater core and see if it cools.
What he said. Also you may want to get a good thermometers and take notes for a/c tech.: Outside/ in cab / water temp / vent all at the same time. also ideling vs running. Sometimes the problem can be a super tiny piece of dirt that sometimes/partially clogs orfice tube or expansion valve.
Make sure the engine fan is coming on with the a/c on if the fan sensors out the compressor head pressure will get to high and shut compressor off see if the a/c works with the engine fan on Manual.my guess is you have a leak somewhere else in the system.
