the blower motor in my 79 cherokee sucks really bad. I have replaced the motor and fan with a new one, but still not enough air to even defrost the window... I have read about the upgrade from the 73 blazer , but all the pictures i have looked at show it applied to other years. My blower motor is in the heater box, under the hood... I bought the one for the chev, and it looks like it will still bolt in, but the motor seems to be the same size as the new stock replacement I put in... Is the chevy one higher RPM or something? DOes anyone else have the same year and heater problem? THe temp is hot enough, but air pressure is weak... any ideas would be appreciated.

 

do those have a cabin filter on em? if so id start there.

 

Nothing from 1979 has a cabin air filter. Nothing. Pull the fan out and make sure no critters have packed the HVAC case full of dog food, or other junk.

 

I pulled out the blower motor, and reached into the heater core box, and there was a nice build up of leaves and pine needles. I got that all cleaned out and put it back together. The flow improved like 5%. I then took off the heater fore and box and found that the hinged flap in the firewall that let's the heat in was stuck in the closed position. For now I wedges a piece of vacuum hose between the hinge and the firewall keeping the door open half way. I now have about 75% more air flow and enough to keep the Window mostly clear. Any idea what actuates that flap? Seems like it would be the temp control switch? Anyhow, thanks for the advice. Up next is cutting the rear fenders. I gave 33 12÷50s on it and the rears rub when I hit bumps..