I have a 97 Grand cherokee larado 4.0. my problem is that when the heat is turned on there is only luke warm air coming from the vents/defroster. I have flushed the heater core, it flows through just fine so i know its not the core. I've also replaced the heater hoses as well as the water pump?

As per your problem mentioned. There are few solved help links to troubleshoot these problems. Go through the list and Click the link below:----

2000 Toyota Avalon: No heat on Passenger Side?

http://whatisbyme.blogspot.in/2012/05/2000-toyota-avalon-no-heat-on-passenger.html

------------

No heat on Oldsmobile Silhouette?

http://technoanswers.blogspot.in/2012/02/no-heat-on-oldsmobile-silhouette.html

------------

Heater blows cold?

http://schematicsdiagram.blogspot.in/2012/02/heater-blows-cold.html

-----------

Heat blows cold on drivers side and hot on passenger side?

http://schematicsdiagram.blogspot.com/2011/12/heat-blows-cold-on-drivers-side-and-hot.html

----------

Hot air on the driver's side vents only?

http://repairhelpcenter.blogspot.com/2012/01/hot-air-on-drivers-side-vents-only.html

--------------

Temperature gauge does not move and no heat when heater is ON?

http://technoanswers.blogspot.com/2012/01/temperature-gauge-does-not-move-and-no.html

-----------

1992 Toyota Camry: A/C Control light Flashing and A/C not Blowing Cold?

http://technoanswers.blogspot.in/2012/04/1992-toyota-camry-ac-control-light.html

--------------

No heat, blower blows only cold?

http://technoanswers.blogspot.in/2012/02/no-heatblower-blows-only-cold.html
----------

Ford F150 Ac only blows through defrost vents?

http://technoanswers.blogspot.com/2012/01/forf-f150-ac-only-blows-through-defrost.html

----------

Dodge A/C come out of defrost vents only?

http://technoanswers.blogspot.com/2012/01/dodge-ac-come-out-of-defrost-vents-only.html

---------

Ac vacuum line on dodge cummins?

http://technoanswers.blogspot.com/2012/01/ac-vacuum-line-on-dodge-cummins.html

---------

Ford ranger AC blows cold through defrost vents instead on cabin vents?

http://technoanswers.blogspot.com/2012/01/ford-ranger-ac-blows-cold-through.html

----------

2005 Chrysler PT Cruiser: A/C Blows Warm?

http://whoisbyme.blogspot.in/2012/06/2005-chrysler-p8t-cruiser-ac-blows-warm.html

-------------

2009 Mercury Grand Marquis: A/C blows Cold From Defrost Vent Only?

http://whoisbyme.blogspot.in/2012/06/2009-mercury-grand-marquis-ac-blows.html

-----------

AC not blowing through Vents on 2007 Chevy Trailblazer?

http://schematicsdiagram.blogspot.in/2012/04/ac-not-blowing-through-vents-on-2007.html

----------

Passenger side temperature is warm air out of dash vents?

http://schematicsdiagram.blogspot.in/2012/04/passenger-side-temperature-is-warm-air.html

----------

These will help.

Thanks.

I would have the thermostat replaced and have the antifreeze flushed or drained out. If the thermostst is over 4 years old and if the coolant hasn`t been flushed or drained out recently, then this will improve your heat situation..

check your blower hoses to see if one or more have come loose or got redirected or the selector switch isn't functioning properly (is it blowing better on defrost as opposed to floor vents, or forward vents, etc.)
Good luck

I tried that but not my heating core is not getting hot just warm. i think they computer is turning it off because it still thinks the doors an closed. This is what im trying to figure out. I felt the heating hosing under the hood and they both feel hot going in and out of the heater. I am getting luke warm air which is better than the freezing air though

Air in the system or a clogged heater core. If it's air in the system, it needs to be burped. Click on my screenname, go down to Tips and Tricks, and follow the tip there on how to do so.

If the heater core is clogged, you'll need to blow it free. Follow the two heater core hoses from the firewall out to the engine. Disconnect them both, put one in a bucket, and use the blowgun attachment for an air compressor to blow into the other one. Then swap - put the one you blew into, in the bucket, and blow into the one that was in the bucket the first time. Reconnect the heater core hoses, and burp the system (again, follow the Tip instructions for that). Usually that will take care of it.

PUT A HIGHER THERMASTAT IN. 190 OR 195 DEGREE

check vent functions to make sure in heat position vents are fully closed. turn temp switch back and fourth so hear movement of heat vents gl

My 1999 limited does this. When i bought it off the guy he said that its because of some flap down by the passengers left foot. In mine the passenger air barely even blows because of this.

check your heater core