2018 RAM 2500 Limited - Heater Vent?

[Don Stell]

OK, guys, here is my dilemma.

I have a 2018 RAM 2500 Limited 6.7L dual zone with heat flow woes.

I can’t get any heat flow from my dash vents, but I get 142° heat from the vents under the dash.

I do not think it’s a blocked heater core, as the heat temperature is within specs.

PS: I forgot to mention that the vents in the dash work in the AC mode.

Thanks!

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[AK Bob]

Looking at the attached heating system operation and diagram makes me think that mode door (9) may be stuck in the floor position.

I recommend scanning the HVAC module for trouble codes to help pinpoint and troubleshoot the issue.

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[Don Stell]

If lucky door number 9 is the problem, how would one repair this door without removing the dash if there is such a way?

Thanks for your help.

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[AK Bob]

If lucky door number 9 is the problem, how would one repair this door without removing the dash if there is such a way?

Thanks for your help.

The mode door "actuator" may be accessible from under the dash on the driver's side.

See location (11) in the attached information.

If the actual door is damaged or broken, the air box must be removed from the dash.

Hopefully, someone who has tackled this job will chime in.

As mentioned in my previous post, first scan the HVAC module for trouble codes to help identify the issue.

There may be bi-directional tests available also.

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[Don Stell]

OK, here is the update: I have a friend who owns a body shop with a high-end scan tool, and nothing in the HVAC section was detected.

We went into the controls in the main menu, and you can choose to blow out the vents in the manual mode.

Hot air comes out of the vents as long as it is in manual mode, but when you select auto, it blows only on the floor or out of the defrost if selected.

Maybe this is the way it operates in auto?

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[5001craig]

I've had three 4th Gens, and I'm pretty sure they all blow out of all the vents in Auto mode.

A little out of the defroster vents, a little out of the dash vents, and then some out of the floor.

I will say that all three trucks have acted differently in auto.

I almost have to run my '22 in manual mode to get everything warm.

I've never really figured her out.

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[AK Bob]

I can honestly say that I have never used the “auto” mode.

I must be showing my age, as I always use the manual controls LOL.

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[AK Bob]

OK, here is the update: I have a friend who owns a body shop with a high-end scan tool, and nothing in the HVAC section was detected.

We went into the controls in the main menu, and you can choose to blow out the vents in the manual mode.

Hot air comes out of the vents as long as it is in manual mode, but when you select auto, it blows only on the floor or out of the defrost if selected.

Maybe this is the way it operates in auto?

I used the "auto" feature for the first time today.

No matter what airflow variations I set manually when I switch to auto, the flow defaults to floor only.

I believe you are correct, and your heating system is operating normally.

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