Hey guys I have a 96 grand cherokee 4.0 and the hear is just warm. The heater hoses go straight into the fire wall where my old cherokee had a control valve in the engine compartment . The water pump and thermostat have been replaced. Any ideas? Thanks

 

Have you tried flushing the heater core out?

 

The 'blend door' could be the issue. It is vacuum operated by the heat lever on dash. Look under the dash passenger side, make sure the linkage is connected and moves freely when heat lever is moved. This should be ruled out first.

Hopefully you will not have to replace the heater core. It is a major pain. Seems they suspended the core in mid-air and built the jeep around it.

 

I have not tried that, but I did flush the cooling system prior to changing the water pump with the heat on. Are you talking about the old school flushing kit and disconnecting the heater hoses?

 

I'll look under the dash, I've only had cherokee's this is my first Grand

 

Do you the two smaller hoses? What i do is undo both of them take a water hose put it on one end and let the other hose drain what comes out, then put the water hose on the other hose then repeat. Make sense?

 

Its a motor that adjust the blend door, not vacuum on ZJ.

 

Thank You for clarifying! From the other side of the world too.

 

:-), and its possible to see/feel and even take out the "control board" on the motor to see if its working. I dont know if it possible to see if the blend door is working if they are broken or something. But when i turn my **** i can feel the motor turning the door.