View Full Version : Defroster Issue

October 26th, 2017, 10:50
'98, 2 door, 4.0 Sport -

had the heat on for the first time of the year, I noticed last year the heat was getting a little weak so I did a core flush and everything seemed to be okay. the defroster gets warm, but only warm enough to defrost the windshield and not really heat the cabin. figured I'd need to do another flush or the inevitable heater core replacement. I switched the heat from defrost to just the vent (little guy with top arrow) and it blows strong and hot. what am I looking at here? hot/cold door stuck in the defroster setting? I've never dealt with this before so I'm not sure how to begin addressing it.

October 26th, 2017, 11:23
Look up Cherokee "blend door" or "vent diverter: issues. The plastic tabs on the doors snap off and get stuck, or slam closed when you turn the heater on full speed. Since you said it blows hot from the vents, I'd say its not your hot/cold door but the door that diverts air to the defroster.

If that's you're problem, solution is taking apart the entire heater assembly which also means taking off the dash. Not a simple project, but if you need to change the heater core or AC parts, do it all at once. Sometimes it can be done by accessing the door lever by removing the radio and digging thru there, if you're lucky.


October 26th, 2017, 11:45
very good... I'll have to see what I can get myself into. I do get some air out of the defroster but very little. so this would seem to make sense.