Derrick Cook

Hi Cherokee brothers! Having an issue with my 2001 grand cherokee. its not blowing air through the vents. ive done code scan and came up with 52 and 56. found a write up on the recirculating door and how to zip tie it to close off the cabin recirculating mode. done that, still no air flow. took the blend doors out and the back one was broken. i used epoxy to hold it back together and was able to wedge the doors upwards and put the plastic door i cut back in to see if it would work. still no air flow. im stumped.

zjhomme

anything through the defroster vent?cruise work?

Programbo

Is there air coming out the defrost vents up on the dash beneath the windshield? If there is any sort of vacuum loss the system just comes out there as a default. I know once I changed my battery and put a small nick in the black plastic vacuum hose that runs along the fender behind the battery and that's all it took to make the sir in my vents not work

94zj318

Your blend door (the door that opens inside the vent when you turn the **** to turn the HVAC system on) may be broken... plastic is brittle and can break over time... you'll have to disassemble your dash to repair it if that is the case... if you turn the **** to turn your system off and you hear the door close, then that's not the problem and it may be a hose disconnection or hose leak that would need to be repaired.

Also what others have already said, does the air come out only the dash defrost vent? That's what the HVAC system defaults to when there's a problem such as the ones I've described above.

00_WJ_4.0

I'm actually having the same issue with my newest jeep, it IS coming out the defrost but that's it and idk if my cruise works because it's not currently on the road. There WAS vacuum lines disconnected for some odd reason, on the intake, I put those on again but it still only comes out the defroster.

dave1123

Derrick, from the sound of it, you have the automatic climate control and when you say no airflow, are you saying the blower isn't working? There is a control module in the same place the blower resistor is on manual heaters and it's controlled by the computer inside the heater unit. You may need a new module. The blower speeds are automatic depending on temperature demand, not your will! LOL!

Derrick Cook

Found that it was the wires were reversed on the blower. Now it blows great! Crazy how from factory they could sell something with the blower wired wrong.

dave1123

I'd be willing to bet that's an aftermarket motor. Generally they come with 2 plain wires the same color with no plug in it. It's a permanent magnet motor so it will run in either direction. The squirrel cage fan doesn't move much air in reverse.

00_WJ_4.0

Somewhat off topic but the guy that came and replaced my fan motor on my furnace should have known that when he mounted the motor on the opposite side of the housing than it should have gone and a hour after he left, with my furnace running non-stop, and the temp not going above 60°, I realized what he had done, this HVAC tech... So I fixed it and my place heated up properly again.. Moral of the story, squirrel cage housings only let air move one way. Lol

actorres72

I recently had the same issue and after scouring all of the internet for good answers instead of a bunch of self absorbed commentary...I did what I had to do...I figured it out myself. It is a great idea to go through all of your vacuum lines to make sure there are no cracks...however before you go on a wild goose chase...you should try one simple trick. Your fan control center located on the middle dial on the 1999 Jeep Cherokee will solve this mystery of the air only coming out of your defrost. Open the rear of the dial where all the multi colored vacuum lines go. There is a spring that goes under a silver plate with a rubbery red stamp looking thing. This rubber stamp goes toward the plastic plate with the tiny holes. Well this rubber stamp will not create the vacuum seal you need here unless the spring is nice and taut. This is the procedure.

1. Remove the white plastic piece where the vacuum lines go (I used my pocket knife to very carefully pry and used my finger to keep one side open while prying on other corner tab then it will come out.
2. Remove the rubber stamp looking thing. (It has white lithium grease on it. Might be a good idea to put more grease here)
3. Locate the spring and stretch this spring but use your common sense here. You dont want to ruin the spring)
4. Replace the spring on dial hole and place the rubber stamp with the silver plate side pointing toward the spring( Do not use the rubber stamp side)
5. Replace the white plastic cover( You'll need to use your fingers to keep the rubber stamp in place while replacing the white cover with tubes for vacuum.

Replace vacuum lines and this should alleviate your issue. You will need to wait for the system to build vacuum suction and your air should now come through your front facing vents if everything else is connected properly.