Cold air only blowing cold air from my heater everything else is ok temparature, engine etc s type jag 2000

THEIR IS A VALVE ON THE RIGHT SIDT OF THE VECHILE HEATER VALVE RIGHT AT THE FRONT JUST BEHINED THE BUMPER THAT NEEDS CHANGIND OR CHECK THE CONNECTIOS TO IT FIRST.

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.

I've had this problem. 2000 GMC uses a closed coolant system. Meaning takes and returns coolant from and to the Reserve Bottle and has little air in the engine and heater systems.
If everything appears ok but no heat. "Air Lock" is the most likely cause. (With interior heater set to full heat) Solution; 1. Make sure water pump works. 2. Drain about 1/2 engine coolant into container. 3 Remove both heater hoses from engine side and flush heater core in both directs through heater hoses with garden hose. 4. Reattach heater hoses in correct locations. 4. Refill engine with coolant. 5 Start engine and run for 2 min., use caution when topping up coolant.
6. Most 2000 GMC have twist off caps with plugs located mid way on heater hoses. with engine cold, start engine these caps may be loosened to allow trapped air to escape. Do not attempt with engine hot due to hot coolant injuries. This may take more than one attempt to remove all air from heat system. 7. Lastly most 2000 GMC water pumps have a bleeder plug,( 3/8" square driver plug) located on the water pump. With egine cold this plug should be removed to remove any air. Reinstall plug with thread sealant.
Hope this helps cheers

heater core,, I got the same problem,, looks like it is under the dash,, if you can help me contact at [email protected]

Remove the plug from the heater control valve to check water flow.If cabin heats up OK then the fault is electrical.If not my be airblock/leak in system.

2000 S-TYPE JAG 4.0 / MY ENGINE TEMPERTURE LIGHT CAME ON AND I SAW THE NEEDLE GO FROM COLD TO HOT AND THE CAR WAS MAKING A CLICKING NOISE. BESIDES REPLACING THE COOLANT WHAT ELSE COULD BE THE PROBLEM?

Replace your heater control valve, its the device that channels hot water either around your engine only or when the valve opens it channels it through your cabin also..
They are quite common to fail on pre02 cars...
if all your electrics are ok, and the car is running normal temps, try feeling the pipes around the valve.. its located behind radiator left side looking down.. could even check all related fuses, just to be sure..
Good luck

your air mix door may be stuck. air mix door mixes air flow/temparature of air coming out. it may be malfunctioning.

my heater only blows cold air please could you give me some advice on this thanks . everything else is ok temp ,engine etc

You have 2 zone temperature control control. The heater control valve has failed and is open allowing the passenger side heater core to stay hot.
It is a very common problem and expensive to repair. It tends to be an intermittent problem and sometimes will work properly.