Fan clutch or compressor? I have a 2003 Dodge ram 1500. This past fall I noticed that the AC wasn't working in traffic while barely moving, once I got moving it worked fine. The other day I started my truck early to warm up because of the cold and my heat wasn't working. I had the truck fully warmed up with the heat off until I got in the truck. I got out and scrapped away the ice but noticed as soon as I got on the road that the heater started working just fine. Does the compressor operate both the heat and ac or could it possibly be the fan clutch? All advice appreciated.