Heater blows cold air

Hello –

To better assist you is your model the Cherokee Classic, Limited, SE, Sport, Grand Cherokee Laredo or Grand Limited and what is the engine size in liter.
Do both heater hoses get hot when the engine is warmed up? If so this is an indicator that the flow is there and you may have a blend door issue. For this we will definitely need to know which Jeep you have as the Cherokee and Grands are vastly different

Read this guide, it will help you figure out what is going on

https://www.2carpros.com/articles/car-heater-not-working

i have recently replaced the engine in my vehicle with on that has 78000 miles on it. I now have no heat, only the defrost mode blows air and its cold all the time.

The reason why the defrost setting is the only one that is working is because that is the default setting when their is a vaccum problem. Check your vaccum lines under your battery a lot of people have reported by fixing that line has solved this problem. Other wise follow the vaccum lines back to the firewall one might not be completely on you may have a crack that is leaking.
Has for you only having cold air blowing out I would check your blend doors. Go to the heater treater website they have videos that will show you how to fix this problem.

my 99 jeep grand cherokee has no heat, the air blows out but blows out cold air. It actually blows out whatever the temperature outside is. If it is hot outside i get hot air if it is cold i get cold air. Please help, no one can tell me what is wrong with it

first feel the heater core hoses with the vehicle hot. they should be hot. tell me what you find.

really sounds to me like your blend door is not working in your car and is stuck in the middle of the temp range.

My Jeep Grand Cherokee Limited has dual heater control (driver and passenger). Driver works fine, but passenger side (defrost, personal, and floor vents) all blow outside air even when you turn the control up to Hi. Change the control from hi to low and back with no change.

I had the same problem I had heat only on one side and then no heat on one side. I t was a blend door actuator which was a dealer item and a dealer job to fix. good luck. the dealer can let you know in a few minutes no charge. If you have them fix it. This is a very common problen only for jeeps from 1999 to 2004 then this system was changed. I personaly think it should have been a recall item . good luck

Heater problem
1999 Jeep Cherokee V6 Four Wheel Drive Automatic 93000 miles
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what could cause the heater to not blow heat? is there a control valve somewhere that could be malfunctional? blower works fine. thermostat is fine.

Check for clogged-up heater hose and the heater core-could be the heater control valve. Coolant level is up to the full mark?

The heater in my 1999 Jeep Cherokee sport does not get hot. The fan works, but it seems the control switch from hot to cool is not funtioning. Air is at best slightly warm (outside above 45 deg) to cold (below 30 deg). need to know how the flap in the box works, (electrical or vac.) and how to troubleshoot problem.

did you check both your heater core hoses to see if they are hot when engine is up to temp?

Air blows freely from all vents. Temperature register up to 210 degrees. Only cold not hot air is blowing thru the vent. Any idea of the problem?

Check the thermostat if it stcuk open and the heater core if its clogged-up, if it has an heater control valve check that too-if all okay-could be door problems, vacuum/actuators and HVAC control module.

I have 1999 Jeep Cherokee classic and the heat is not working what can i do? I replace the thermostat.

Feel the heater hoses near the firewall, after your rig is at operating temperature,......if they are as hot as your upper radiator hose, the thermostat is probably not the problem!

Observations? Other observations?

I do not know your rig well

I will try to help you

I'm still here!

The medic

Are they uncomfortably too hot to hold in your hand very long (all mentioned, after you reach operating temp)......or cooler after it idles a while, and really hotter just after a drive (if you check it quickly after the drive)

Does your temp gauge fluctuate from "higher" while driving to lower while "idling"

You can respond below at "add a reply"

The medic

By the way---i do not know you, so i am not directing this to be mean!

I do this to everybody, who is not "me"!

Did you install the thermostat prior to having this issue or after--even so, is it sitting with the spring down and pointy side up,
Have you had the heater hoses off and maybe misrouted them?

Really good one---are you full of radiator juice?

Is there any sort of "water switch" on the heater hoses---between one end of them, to the other?.......if there is, maybe its stuck partially shut......it might can be completely removed (now that it's winter time) and the hose replaced in full length or just the valve be replaced with a suitable coupler till you can do better!

Are they old and squishy, and maybe the water-pump is sucking the return flat?

Are there any kinks in the heater hoses?

I'm about to hit the hay--see you in the morn!

I will leave you with some thing to try

Take loose the highest heater hose on the engine--at same time watch the water in your radiator--is it falling as if you just bled the air from an air pocket?

If no results there, continue with this:

Connect a long heater hose from the water pump to the fitting in the engine (completely by-passing the heater core)how hot does this line get?

While that is loose, force water thru the heater core with a water hose---is it flowing freely from the open side??

Heck, if the water hose is connected to every heater hose in the system, (one component at a time) does it come out the opening on the other end of each component

Night--night

That oughtta keep you up all night!

The medic

Sorry, between my 1st and 2nd answer, "damonre" sent me a message, we were discussing the heater hoses and the radiator upper hoses' temperature!

The medic

No existing mechanincal problems other than addition of about two pints of cooling fluid monthly. engine overheated on a local errand. went home, filled radiator and ran to warm up - still no heat from heater. oil pressure spiked to 80psi. checked oil could not see any "bubbles" or water in oil. oil level drops to correct level when engine is off. no smoke out of exhaust. purchased new and changed oil every 5-6k miles.
any suggestions?
thanks
jim coster, pittsburgh, pa

Ok I would check to see why it using coolant. I would call around and find a shop that can do a chemical test on the radiator to see if it has a blown head gasket this will answer this with no guess work. Now as for the heater these systems are very hard to get full or burp the bubbles out so you may need more coolant you will have to check if all this checks out then get back to me and we will dig deeper into the heater system to see if the heater control valve may be bad. Thanks and Merry Christmas.

hi, thanks for your reply and merry xmas to you also!
had jiffy lube change oil and no decernable water was found. heater is now putting out heat but oil pressure is still pegged at 80psi. i will try the coolant head gasket test. will continue going down your list of possibles: next is new rad cap then a new oil pressure sending unit sensor then new oil pump or oil pressure relief value then new water pump. will keep you posted when problem is solved for benefit of other jeep owners.
great site... thanks for actually replying... i'm always scepticle about sending money to internet sites.
jim coster

Ok I would first replace the oil pressure sending unit so see if that fixes the oil pressure issue as it usually not to expensive. As for the water I take it that it the radiator was very low? If it was then do the chemical test to rule out the head gasket leak. Otherwise it sounds like you are on the right track. Thanks again.

I also own a 2000 jeep cherokee from new and can tell you that after 80,000 mi. you will need to replace the hoses and thermostat and do a complete flush of the system. This will prevent you from having a break-down around 102,000 mi. like I did.

Chances are that if you are losing coolant, you have a bad hose somewhere. I live in the mcKee's Rocks area and I use a repair shop called C&D Auto Service located right on Chartiers Ave. across from Pat Catans.
412-331-3774

They have been reasonable and fast. Oh and before you spend good $ on sensors and such, try disconnecting the battery for awhile (15 min.) and then reconnect it. That should solve the problem with the oil pressure gauge.

Unless you like spending money on your Jeep.

My heater is not working. I just changed the heater blower with a new one. The blower still does not work I live in Alaska and need a heater very bad. Could it be the resistor that is bad and if so how can I find out without speding more money. Please help as I am a lost. There is not air blowing when I use any setting on the contorl hot or cold.

Is air blowing out of vents at all or is the air just cool? Usually when the resistor is faulty you still have heat on the 4 setting. .

My jeep blows out cold air... the ac button will come on by it self and the temperature gadge when you turn the jeep on automatically goes from L (low) to the center of the gadge and slowly very slowlys goes up to H (high) but never reaches high.. what can be the problem. so there is no heat at all it just blows out cold air

check and replace the thermostat and if necessary check/replace the engine coolant temperature sensor. the thermostat should clear your problem up, unless . the control panel is faulty, lets go with cheapest first.

which is your thermostat

I recently purchased a used 2002 Jeep Grand Cherokee by owner this summer. When the weather turned cool, I turned the A/C to Heat and adjusted the temperature to 85 degrees on the dash. I waited for the heat to start coming out of the vents but still no heat after 1 hour. Could this be a sticky heater control valve? What is involved in fixing this? Do you have to pull out the dash to fix it?
What is the best way to fix this problem? Lastly, How much can I expect to pay a dealer to fix it? Thanks for your time. Tom

go to www.heatertreater.net I did, 120.00 fix, and dealer is about 1200-1500 it worked awesome!!!