2000 No (Very Little) Heat Heater Core Possibilities

I've had no heat for years, may want to fix it this year.
newer water pump & thermostat, newer engine.
will blow slight heat after complete warm up but not enough to keep up in freezing temps.
i've flulshed core in past but it only seem to help temporarily.
AC system works great.
don't ever remember smelling fluid or seeing a leak on passenger side.
my question....
how do you rule out the fact that it may be blend door or another complication?
i'd hate to do all the work for nothing.
is there someway to test or observe that everything else is working?

When the engine is warm, turn the heat on high and fell the two heater hoses coming out of the core, if they are cold/barely warm then you have a restriction in the coolant going through the heater core.

sidewaysstarion said:

When the engine is warm, turn the heat on high and fell the two heater hoses coming out of the core, if they are cold/barely warm then you have a restriction in the coolant going through the heater core.

Click to expand...

If both are really hot with little temp drop, then you might not have air blowing across the core.

Sounds like you need to check the heat door it may not be going all the way over to the heat side , it probable stuck on the cold side .

i'll check heater hoses today.

if its the blend door? how would i check that on a 2000 XJ?
is that the one controlled by the little stepper motor under dash or would this be vacuum controlled?

The blend door actuator is the electric stepper motor. Mine failed on heat in the summer time.

last time i checked it rotates fine but that doesnt mean the internal parts are working. ill have to look into that