My Jeep only has about 120K miles and the heat no longer works at all. Any input? A friend told me that the Jeeps have trouble with a Blend Door.Any one had this problem? If it is the Blend Door,where is it located and how hard is it to replace? Thanks!

Have you checked to see if is a blocked heater core? Are the heater hose temps hot in and warm out?

Air in the system. .my ram was bad for that air bubbles in water system no heat ..

Had 3 Cherokees and never a problem with blend door.
ALL were coolant/coolant delivery issues when no heat. They were 97, 98 and 99's.
They are WELL known for coolant issues esp 4.0's.

remove or cut the hoses to splice them, flush backwards with water coolant out of the heater core,blow out as well I don't use compressor(too much pressure) then fill with white vinegar let set 10 minutes or so flush and refill! Low cost works most of the time!

Do you hear any strange noises when switching from hot to cold and back? Is it a dual system? plastic shafts on Blend air doors break. there is a kit to fix them from Jeep, do them a lot.

Just noticed is this a Cherokee or Grand Cherokee? If it's a Cherokee yes look for a clogged core!

I just back flush mine with air, but I turn the pressure down to bout 25 psi and did quick burst.