Climate Control - Cold Air Only Problem

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The engine comes up to temp and operates in the middle of the gauge, but the air coming out of the dash, regardless of setting (Auto or the others), the air is cold. The fan works at all speeds, but for the past two days it only blows cold air. We have had subzero temps here in Minneapolis since Christmas. Warm air was formerly available, but no longer. Has anyone else experienced this problem? Any ideas?

 

[ltd02]

Blend door stuck or actuator has failed. I think the actuator is easier to get to in the KK. It's a B%$#* in the KJ.

 

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I took advantage of the first above zero day since before Christmas to pull out that blender actuator,

The actuator operates properly. Using a 5/16” Allen wrench, I turned the blender door to various positions and still no warm air. I put it back together.

Before I started, I saw a dashboard message about a Heating System Problem; I don’t recall the exact wording.

What should I check next?

 

[ltd02]

Is your coolant level okay?

 

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Coolant level is good, though it intermittently leaks somewhere. I did install a new radiator last summer.

The message is "TPM System Check", which is tire monitor and not temp. So never mind that message; one of the tire pressure sensor stopped communicating with the mother ship.

Any ideas why I cannot get heat?

 

[KKinTexas]

Top off your coolant level in the radiator and in the overflow bottle. A few run cycles amd it should be air free and giving as much heat as possible. Do both the heater hoses going thru the firewall feel hot? If not, you probs have a heater core issue. If both hot , then it is a distribution box issue, especially if actuators are working.
Do you get heat from any vent or mode position?
If actuators dont move, then it is either actuator or control panel. You could get those off ebay or local salvage yard.
These things are nit that complicated, just difficult to get to. You should also try flush and backflushing your heater core. Takes 10 to 30 minutes to do with bucket and hoses. Then at least you know if that is clear or not.
Good luck!

Sent from my SM-G930V using Tapatalk

 

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We are presently replacing the water pump, thermostat, and fan clutch. While coolant is out, I would like to pull the hoses off of the heater core and back flush it with water.

How do I determine which hose is core inlet and which one is core outlet?

 

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Anyone know which pipe is which on the heater core. I want to flush in the reverse direction of flow. Thanks

 

[ltd02]

Anyone know which pipe is which on the heater core. I want to flush in the reverse direction of flow. Thanks

This is for an 04 but can't imagine they would have changed that much. Just follow the hose from the WP back I guess.

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Could disconnect one heater hose and bump the starter and see what end the coolant comes out of. Might work?

 

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Inlet/Outlet

Neither hose is connected directly to the water pump; they both come out of the block, adjacent to one another. There is no control valve, which is sometimes present to regulate the coolant going into the heater core.

The hoses were difficult to disconnect from the heater core, so I warmed them up with a heat gun set to low (hair dryer temperature), which allowed them to break loose.

 

[ltd02]

I'd love to see a picture if you can get one.

 

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Itd02: Thanks for the diagram. We back-flushed the core last night and forced out a lot of junk.

 

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Apparently, that black junk that we back-flushed out of the heater core had it blocked. The heater and defroster are back in action, just in time for winter.

We used a funnel and an old brass hose nozzle to supply water to the outlet and caught most of the back wash in a plastic bottle.

 

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That core contained some serious sludge, likely stop-leak from a previous owner. Using a funnel and an old brass hose nozzle on the outlet, I blasted the core, forcing coolant and large black chunks out of the inlet pump and into a plastic bottle. She blows hot air now. Good to have, as yesterday morning temperature was 4 degrees in Minneapolis