heat works fine on the right side. There are a few possible things I think it could be. Plugged heater core on the right side (hopefully not), plugged hose on the right side (not likely), valve for the right side (more likely), or the temp control switch thingy in the car for the right side. I am sure that this is not a completely uncommon problem, as I think I remember others having this problem before. So what was the cause? the fix? the cost? -Michael McCoy