02 navigator front heater blows cold air

The heater core may be plugged with rust. Good way to test it is with the engine warmed up put the controls in heat mode and then go under the hood and locate both water hoses going t the heater core. Hold on to both hoses to see if the temperature of both hoses are the same. If not, no water is getting into the core. . If the temp is the same, then control vacuum is not working. There is a check valve in the line to the control head that prevents vacuum fluctuations from moving the blend door when accelerating. Check it.

warmth comes from the heater in the car
if it is climate control check the climate control module
check for heater control in the vent settings as the hot water tap may not be turning on

i'd guess at an air lock in the front core , try bleeding the system turning the temp from hot to cold with engine running and while bleeding watch for any drop in coolant level as dont want more air entering the system

Sounds like your heater coolant hose door flap is broken or loose. May want to check behind the heater controls, if your components are mechanically operated. If electronically, may need to perform more troubleshooting before replacing this component.

To troubleshoot this types of problem,click the link below :----http://howtobyme.blogspot.in/2012/02/heater-blows-only-from-defrost.html
--------Go through the procedure to confirm the issue.

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http://howtobyme.blogspot.com/2011/11/engine-overheats-and-heater-blowing.html

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

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

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---------Car heater blowing warm, but not hot air? http://schematicsdiagram.blogspot.com/2011/12/car-heater-blowing-warm-but-not-hot-air.html-------- Heater/AC blower motor not working?

http://technoanswers.blogspot.in/2012/02/heaterac-blower-motor-not-working-on.html

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A/C, heater, defroster fan, not working? http://technoanswers.blogspot.in/2012/02/ac-heater-defroster-fan-not-working.html Heater problem? http://technoanswers.blogspot.in/2012/02/heater-problem-on-isuzu-trooper.html---------

This will help.Thanks.

To troubleshoot this types of problem,click the link below :----http://howtobyme.blogspot.in/2012/02/heater-blows-only-from-defrost.html
--------Go through the procedure to confirm the issue.

------
Engine Overheats and heater blowing cold?

http://howtobyme.blogspot.com/2011/11/engine-overheats-and-heater-blowing.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

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This will help.Thanks.

Hope I was avle to help, glad you up and going.

Check for a vacuum leak. WHERE is the magic question.

Shelly,

Buy used parts at car-part.com. Look on page with * to find the cheapest part. Coud be your temp blend door (#2) may not be moving back and forth. Or, you are not getting hot water to the rear heater core.


You may have to crawl under the truck and feel the heater hoses to see if they are hot. You will find a group of 4 lines, 2 for heater and 2 for a/c. If hot, you know hot water is getting back to the heater core. If not, there may be a hot water vave that's not working. Not sure if EXP. has a water valve for rear.

Let us know what you you find. Good luck.

try changing the thermostat if thats not it check and see if you have water leaking in the passenger side floor board if so then you need a new heater core