96heep

I have a1996 jeep grand cherokee 4.0I6
the heat is like luke warm only gets to like a temp inside the jeep so you cant see your breath anymore. I replaced the thermostat and still does the same thing. Im thinking its the controls inside like the hot/cold position selector because if you hold your hand on the vent it stays the same temp. I did order a new one that should be here soon but figured id ask if anyone has had or would know what the problem is thank you.

PINIT 141

flush out the heater core. quick way to tell is grab the heater core hoses at full running temp and see if there hot. if just a little warm its prolly stopped up with junk.

96heep

I grabbed them and they are hot. Thats why i dont get it i dont think it could be the heater core just because ive been told when they go they leak and you smell the anti freeze. I just have no clue what it could be thats why im gonna try this with a different Controler i found it on ebay for $40 so ill give that a shot if not i dont know what it could be lol.

jomps

if its not the switch I know the wjs had real trouble with blend doors



so it may be possible with your zj

cparker688

Do you have the dual-zone controls? If you do, the system has a self test feature you can use to see what error codes are given. My blend doors were trashed so I got the kit from Heater Treater for like 100 bucks. Took me two hours tops and now my heat is good enough I have to turn it off sometimes just to cool back down. The blend doors need to form a complete seal whether in A/C or heat position and over time the original foam on them wears off and the plastic doors break and fall causing crappy heat and/or A/C. Do you have cold air coming out of the passenger side yet while the drivers side is lukewarm?

Note: I have a WJ so not sure if this applies to you but hope it helps.

94zjdriver

I have the same issue. sometimes the heat is not what it should be... hot hoses, new 195 thermostat and good water pump.. Don't know about the switch

96heep

im not to familar what is a blend door? lol

rizmonkey

My 2001 GC blows cold out the passenger side and barely anything out the driver's side. Do you have a link to the Heater Treater? Was it hard to install? Anything to be aware of? I'm not going to do anything until Spring since I don't want to work on it in the bitter cold so I just have to live with it a couple more months. It sucks !

RIZ

1ATony

I have the same issue with the 97 ZJ i just bought. I'm going to try to flush my heater core with the hose as soon as I get a warm day around here to do it.

jomps

I dont know about zj BUT FOR THE WJ,

research this and there is alot on jeepforum too....not hard at all to take glove box out and cut into dash to access the blend doors on the WJ. was having same issues on 2000 gc...i didnt even buy replacement parts...just taped the blend doors shut (high heat position) and taped access panel back on....cant control blend doors but got full heat, and this summer will take doors out and got full ac...may never buy new doors


although my passenger heat worked and driver didnt....depends; you can pull whole dash and keep dual climate, cut panel and install one door for single control, or heater treater has option to cut hole and add another motor to keep dual controls

96heep

Ok so a little update i replaced the heat/ac contorler did nothing but i flushed out my heater core i dont have full heat but its blowing out alot warmer then its been i can drive now without my hands freezing to death and its defrosting the winshield so thats alot better lol
thanks for all the help tho :-)

JayP71

Having the same issue with my '95 ZJ. Replaced thermostat and getting ready to replace a cracked radiator before flushing the heater core.

Don't think this is a blend door issue* as the AC works great. is there any kind of valve in the engine compartment that could be stuck?


*I've owned too many Fords to not catch a blend door problem, LOL.

fletch469

hey on my wifes wj 2003 it was a vaccum line under the battery box was cracked

jomps

not saying it is the blend door, but if it was broke and sitting there it would only allow cold air in anyway....happened to our wj

JayP71

Partially clogged heater core. Will get it flushed in the next couple of days. Replaced the radiator (cracked)*, and the heat output has increased somewhat.


*My, but what a fun job that was.