Heater blowing cold air

Check to see that both heater hoses are hot when engine warm. If they are then it is most likely a vacuum issue or a control actuator/solenoid (blend door). See the attached guides for vacuum issue and blend door replacement. I have also attached the air flow/vacuum diagram for your vehicle.

https://www.2carpros.com/articles/replace-blend-door-motor

https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position

Check these guides and the diagrams below and get back to us.

Car has dual front heat system. I get heat to defroster and to right passenger side, but driver's side blows only cold or, at best tepid air. Could this be the heater control valve?

Additionally, there is a sporadic ticking sound under the dash, in the vicinity of of the heater controls (center area). It sounds like a gear slipping, perhaps. It is not loud. A/C seems to operate correctly.

Hopefully, you can offer some guidance.

That sound is most likely the door actuator that is causing your problems. You will need to get under the dash and find the one that is making the noise and watch it to see if it is moving the door or not. Most likely is broken and not moving all of the way into position. Could also be that the door is broken, when you remove the actuator, manually move the door to be sure it is not broken inside the HVAC box.

I only get hot air from the heater when the car is moving, when idling the heater blows only cold air.

Check the thermostat and coolant level.

Your heater core may need to be back flushed. Do you have orange or green coolant?

Green coolant.

The orange has been known to cause some build up/deposit problems is why I asked.

I have no heat on the drivers side, passenger side is fine. No problems with A/C, only heater.

The vehicle has two blend air doors that determine if you get heat or AC. It sounds like one is stuck.

My car seems to not have any heat while I am in park, but once I start driving It will heat. What could be the problem? There is antifreeze in it.

Are you sure the coolant is full? When it is low, coolant will not make it to the heater core at low RPM's. However, when you rev the engine and speed up, it will circulate.

Let me know what you find.

Six cylinder, automatic.

Is it the circuit or the fan?

What is it doing? Is the blower motor coming on?

I am not getting any hot air out of my vents when the heater is turned on. The temperature gauge starts to move to hot then I get a little heat and the temperature drops and then no more heat?

Is the coolant full? Check it when cold.

It has some fluid in the resvior and a lot of crud on the cap.

Bring the engine to operating temperature and feel the heater hoses going into the firewall. If one is warm and the other is cold, try back flushing the heater core.

My heater did that, I checked the coolant it was very low. So upon further inspection I found out my intake gasket was leaking and that is why my coolant was low. I got it fixed and my heat works fine and my engine did not explode. So get it checked if your coolant keeps getting low.

PS: This year and model are legendary for having faulty gaskets. Look around the engine for coolant in places that it should not be.

3.1 and 3.4 were both notorious for that. At 134,000 I am surprised it was not already replaced.
Congratulations!

I flushed the cooling system and the leak has gotten worse. I cannot afford to fix the gasket right now, but I do believe that it is leaking. Thank you for the responses.