I know this has been covered a million times, I've read the threads, but still am stuck on my understanding of the problem.
I have had no heat for a while and it's starting to get cold now. I flushed and back flushed the heater core and it did not solve anything. When the heat is off, both heater core hoses are similar in temp, with the heat on the lower hose is cooler, this means that there is flow through through the heater core correct? t-stat is working as it should. I'm guessing an issue with the blend doors? The problem with this is I do not understand blend doors what so ever...
I'm looking for trouble shooting ideas before I rip the dash out and replace the heater core
Thanks in advance

 

I would lean towards the blend door or the blend door actuator. The door is only held in place by plastic so one of the pivot points can break. It is more common for the actuator to be the problem, some have luck taking it apart and cleaning and greasing the gears.

 

in my 98 the temp control cable was loose under the dash and it would not push the lever. if i helped it the door could be moved and i got a little more heat. you can see it on mine.move the control and see if anything moves. i flushed mine 2 ways,didnt help much. 08 has cables,not motors?
in 40 deg weather i need to drive 3 miles to get temp up and get heat in my 2000.

it sounds like your core is ok if temp changes in the hoses huh? heat is not getting out anywhere??

 

Thanks for the quick reply I will have to give that a try, what's the easiest way to get to the acuator?

 

Thanks for your reply, I am not getting any heat what's so ever, but because of the hoses I was also thinking the core isn't the issue. how'd you access the door to see if it moves?

 

i was talking of the 98. never looked on my 2000. dont know what you have, and, im no jeep expert!!new 2 months ago.
look under the dash for cable/ linkage??

 

Found it passenger side beside the trans tunnel, the actuator motor is bad, so I have found the problem. Thanks for your help!

 

Mods this thread can be closed or deleted or whatever magic you guys do

 

great!!

 

A blend door is just that a door that moves left to right.What it really does it change from heat to ac,When you switch the heat or ac on it moves to let that air move.Sometimes they break or not work and can be stuck in the ac position even tho you have it set to heat.And with it blocking the heat side you get no heat.Most of the time when the heater core goes it it will leak antifreeze in the passenger floor board or blow steam out the top of the dash.

 

Good to know, thanks for the info, I now know how blend doors work! I turned out the issue is the actuator. Thanks for your help

 

I'm glad you got it fixed and its a easy one.And be happy the xj is simple some new cars have 6 or more blend doors on them now lol.