Recently got myself a 2000 4.7 4x4 Dakota. Have a couple things to fix on it, mainly getting no heat in the cab.

I have changed the t-stat, refilled coolant and bled the bubbles out.
Still no heat coming out of the vents.

Temp gauge reads about 90C (194F)

Also the bottom radiator hose is ice cold and one of the two heater core hoses is also ice cold. The others are warm, I can put my hand on them without any problems. This was true before I changed the t-stat also.


This might have nothing to do with it but the position **** for the vents only does Defrost in any position except when on OFF. I'm wondering if the temp **** could be broken too? I heard they are electronic operated instead of cable. This could be it?

 

Hi and welcome to the forums.

The heater controls are vacuum operated in '00, not electric. The blend (temp) door is cable operated. They default to "defrost" if there is no vacuum.

Under the hood there is a check valve near the brake booster, see the pic, if it fails shut you will not have vacuum to the controls.

The lower radiator hose may be cool it's the return back to the engine.

Both heater hoses should be hot though. You may have a blockage in the core, it's very common. Try backflushing. Remove both hoses and try flushing it in both directions.

 

I'll check the check valve tomorrow and try flushing the heater core also. It's pretty cold up here averaging -4F this week.

 

Where's here? You can add it to your profile.

It's been in the teens and 20's in MA.

All you can really do is pull the valve off and see if you feel any vacuum. It should be strong.

 

Right, I'm Near Montreal. Added to profile.

What happens if I by-pass the check valve?

 

If you bypass the check valve as you accelerate/decelerate the doors will change position. You'd have it coming out the dash one minute and out the defrost the next.

For testing, not a problem. Just take it out and see what happens. You'll have the strongest vacuum at idle so the doors should definitely be working then. If not, you'll have to start checking the HVAC lines.

 

Is there another term for the check valve? I went to a couple places and no one can find the part.

 

Try Mopar: 4549209 or Autozone: 47149