Why does the air conditioning in your 1997 Jeep Cheerokee blow cold but randomly switches from blowing through the vents and the defroster?

Answer 1

vacuum controlled doors ...vacuum leak or a pen or pencil down the vents....look at some pics Everyone should have a manual for their vehicle, and the library should have a professional shop manual available in the reference section(make copies of the right sections) read up and fix it like a PRO! :) good luck

Answer 2

it sounds like the blend door actuator has gone bad it could be vaccum operated or by cables either way i would check to see if either one of the vaccum lines for the actuator has come loose or if one of the cables has slipped off there by leaving the blend door in defrost only

reply to this answer: I have a 2000 Jeep Grand Cherokee and have the same problem , I took the info that the dealer said it was a vacuum problem. I found a vacuum line on the passenger side running along the top of the firewall and then down, there is also what looks like a ground strap from the firewall to the engine right above the valve cover , well this ground strap was touching the vacuum line and obviously this ground strap will get hot because it's attached to the engine. The ground strap melted the vacuum line , I cut out the melted section and attached the two ends with a coupler. Problem solved !

Most likely the vacuum line coming off the right side of the intake manifold just below the throttle body. Look for a small line dangling and reconnect...easy!

Answer 3

Bad blend door actuators or plugged up doors from debris etc. To fix this you will need to remove the dash completely. Stupid engineering....

Thanks for the info. do you know where I can get the heater housing unit ? that is what someone said I needed to replace.

I've never heard of it called a heater housing unit. This other person is probably referring to the condensor box where the heater core and air conditioner A-frame is located. The fan is attached to this box. The box also serves to remove humidity from the inside air. If you get air blowing out of some vents and not others you have a blend actuator door problem. These are little doors that open and close in the duct work behind the dash that direct air flow to the floor or defrost etc. These doors get jammed with peices of styrofoam from the lining of the condensor box as well as other debris and are sometimes accessible without totally removing the dash. If, when you turn on the fan switch, you don't hear the air coming out anywhere then you likely have a bad fan or switch or perhaps a blown fuse. The proper fuse is located behind a small plastic door on the side of the dash when you open the passenger door. It should be fuse number 17, a brown plug in fuse rated at 7.5 amps. If the fuse is blown and then blows after you replace it then you have an electrical problem that needs to be addressed. I would try to replace the fuse and if that doesn't work take it to a reputable dealer or heating/AC guy for an estimate. Removing the dash to get at parts is VERY expensive due to the time it takes and therefore the labor costs. Hope this helps.

Answer 4

Either you need to pen your vents or there is some vent obstruction.

Answer 5

the mode door inside the hvac unit has most likely broken causing to to default to defrost. sometime the actuator is at fault, wither way the dash has to come out