rojo diablo

Need a little help. I have a 2000 jeep cherokee XJ having heating problems. Changed relay, resistor and blower also have flushed heater core. both heater core lines are hot, yet still no heat. I have a **** type temperture control and it changes air from cold to luke warm. Need help on what should be my next step in checking the system

TrekkerJmm

Hi and welcome to CF from Tj...Did you try changing thermostat with a new 195? it may be staying open all the time also what does the temp gauge say...Tj

NapaJohn

Blowing cold air or nothing blowing at all?

TrekkerJmm

"both heater core lines are hot, yet still no heat. I have a **** type temperture control and it changes air from cold to luke warm"
he says he is getting "Some" warm air so thats why I was thinking TS...Tj

LeeVenHawk

I have the same issue in my 98 and it's below zero here. I have flushed, used clr and vinegar, still no heat. The core will not transfer heat.... I know what I have to do but I won't say it out loud.

roach1143

ive owned my 96 almost 4 years now and never had good heat, just lukewarm, enough to defrost the windshield after about 20 mins
i just wear gloves and a scarf in winter

rojo diablo

dash temp gauge shows 210. compared to turning the temp control to cold which blows cold air turning back to hot gives me luke warm at best

LeeVenHawk

By the color of the fluid that came out when I flushed after I bought it mine the core has to be covered in crud... Maybe even bars leak or something was used in it.

Crazy Cherokee

I have the same heating problem in my XJ. I dont know what else to do, you guys atleast get "lukewarm" heat, I absolutely get NO heat. I live in south texas, and although it does not get very cold over here, I would like to use my heater for when it does.Ive been reading thru prior threads, and have tried and checked parts on my XJ, but she just doesnt wana work.

Balazar

I just bought an 86 xj 4x4 2.8l v6 and the heater doesn't blow hot air at all. Only cold air comes out. Both hoses to the heater core are hot and I just did a coolent flush & fill. Could this problem be related to the heater control? The temp guage reads 210 and im fairly sure the t-stat is working because I feel the two hoses to the heater core are warm. Also the air only seems to come out of the defroster vents up by the windshield and not the dash vents no matter how I mess with the controls. Vacuum leak? If someone could please give me a good understanding of how the heat/ac control works im sure I could do a good write up on this.

Btw im in vail colorado and we are having record low temps right now. Not to mention the 18" of snow on my unpaved & unplowed road. Please if you know anything about the heater control post it.

TheCheif

Have you checked out the door in the air box that blends the hot and cold air? the door my be staying mostly shut. that would explain the luke warm air. Or the linkage is working incorrectly and may need replacement.
good luck!

tjwalker

Your best bet at this point would be a flush of the heater core.

I normally try to flush with a garden hose (both ways), but if that isn't enough, I use the CLR method. If the heater core is truly suspect here, you have nothing to lose using the CLR technique, as changing out the heater core is a PITA.

Balazar

Yes the door linkage was for lack of better words a failed attempt at ghetto rigging with duct tape.

Just so everyone knows what we are talking about the heater control unit in the dash has a control cable that links the temperature adjustment slider to an arm that controls the hot/cold air mix inside the heater (its under the dash on the passenger side close to the center console). If the linkage is damaged than the hot/cold slider will not function properly if at all.

I will have to get the control line from a dealership but thats not my biggest concern at the moment. I just ghetto duct taped the door control arm in the position I wanted because its -30 where I live right now and I don't give a damn.

There are a few more problems I am still experiencing with the heater. First off it only blows air from the defroster vents. No matter witch mode on the heater I select (defrost, heat, or vent) Second the fan doesn't blow hard enough to satisfy my lust for warmth. It seems to be dying and I will probably need to replace it. Third the peanut bulb behind the heater control unit is out. Lame but an easy fix.

After lots of reading I have found this page with a heater system schematic and vacuum system diagram in pdf. I then found the control arm that opens/closes the floor vents (its under the dash on the drivers side next to the console). It's controlled by a vacuum line that for me was stuck in the closed position no matter what position the control unit selector slider was in. I still have not found the dash vent open/close arm. I did find no less than three damaged vacuum lines under the hood and repaired them but that had no effect on my heater issue. My tranny shifts much better however. I obviously have some vacuum line issues and lets face it vacuum line diagrams tell you how the system works but not how its physically built so it may take me some time to sort this out and do a good write up. I have been taking pictures so it should be decent. If anyone knows a good deal about the vacuum hose system a push in the right direction would greatly be appreciated.