if you've still got the stock blower motor, then you should probably upgrade to the chevy blazer one. there are lots of threads on here about it. My stock blower motor worked just fine, but with the defrost on, it would not clear the windshield, even after driving for 30 minutes. I switched to a chevy one and now the windshield is mostly clear after 5 to 10 minutes.
77 CJ-7- AMC 360, Edelbrock cam, MC2100, Fenderwells, CJ T18/D20, Chevy D44/EB 9" rear, Trutrac f/r, 4.11, SOA, 1.25 lift shackles, 35x12.50 BFG KM2s, Shackle Reversal