I had the same problem but only the defrost setting would work. There was no hot air either. Check the vacuum lines at the back of the climate control unit. If they come loose the heat will not work. I don't know if this will solve your problem but as the first answer said. It is a huge pain to get the blend door actuator. More than likely the dreaded "blen door" common problem with the 97's and 98's. You have to pull like half the dash out to fix and the part is a couple of bucks. Good luck with it.