2017 Dodge Ram no heat blowing from vents un when heat is on.

Ryan Poulos

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By top 'motor area' ...are you referring to the engine, or blower motor? I assume engine. First make sure the engine is operating at it's rated temperature. I had a diesel that was running at 160 and the difference in heat output in the cabin between 160 and 185 was enormous. Like night and day. There could be a cooling issue to iron out (T-stat or another).

Well, track down that hissing area. If your defrost was on prior to shutting the vehicle off, it could be the A/C pressures equalizing out and mimicking the sound of leaking antifreeze ...because usually A/C comes on when the defrost is on. Or you could have a leak to track down. Is there a 'film' on the inside of your windshield? I mean the possibility of a heater core leak? Or 'girgling' (air bubbles) inside the heater core after you start the vehicle in the morning? That could point to a heater core leak. Even if your truck's heater core is leaking it should still provide heat, unless it's plugged. If they used tap water after replacing the engine's, yeah, that helps create mineralization inside the tiny passages of the heater core vanes. A guy should use filtered/RO water only (ideally). A plugged heater core can also cause a no-heat situation. Just because the hoses are warm doesn't mean you have proper flow through the heater core. The outside passages could be open, and the middle ones plugged.

If you knew someone who had a 'good' scanner, it would be real helpful to get into the HVAC control module and check for HVAC codes. Then perform an HVAC doors sweep test to test the blend door motors and full range actuation. During normal operation, the blend doors cycle and the computer notes when they reach full open and full closed ...so the computer know's the position of the blend doors (ie 30% or 72%). Motors can fail, and so can the hinges of some doors ...or where the motor connects to the door itself. Also, an outside air blend door or motor (to the cabin or the hvac box) failed (or the hinge busted), the heater can still provide heat, but not enough to overcome very cold 'fresh' outside air on a cold day. In other words there 'could' be more cold air entering the cabin entering the cabin than the heater can overcome (making it 'feel' cold inside). Or, if it was like our Jeep when we got it (used), it had multiple blend door issues the previous owner had not addressed ...and was a mess till we got it sorted out. Some of these blend door issues I've outlined may vary depend on the model truck you have (basic or dual-zone hvac). The dual-zone and more complex units tend to have more possible fail points.

Another thing you could do if you suspect a heater core leak, is pry up your pass door's sill plate and put your hand under the carpet (or matt) and feel for wetness under there. That's a pretty good sign of a heater core leak.
Thank you. You gave me a lot to cover. Im getting into it later today.
My truck also got hot today. I was idling in my car waiting to pick up my kid and it pegged the temp gauge. Nothing leaking. Still hissing. I will find the hiss and reprt back. Thank you for all your input here.
 

Ryan Poulos

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Location
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Ram Year
2007
Engine
5.7
By top 'motor area' ...are you referring to the engine, or blower motor? I assume engine. First make sure the engine is operating at it's rated temperature. I had a diesel that was running at 160 and the difference in heat output in the cabin between 160 and 185 was enormous. Like night and day. There could be a cooling issue to iron out (T-stat or another).

Well, track down that hissing area. If your defrost was on prior to shutting the vehicle off, it could be the A/C pressures equalizing out and mimicking the sound of leaking antifreeze ...because usually A/C comes on when the defrost is on. Or you could have a leak to track down. Is there a 'film' on the inside of your windshield? I mean the possibility of a heater core leak? Or 'girgling' (air bubbles) inside the heater core after you start the vehicle in the morning? That could point to a heater core leak. Even if your truck's heater core is leaking it should still provide heat, unless it's plugged. If they used tap water after replacing the engine's, yeah, that helps create mineralization inside the tiny passages of the heater core vanes. A guy should use filtered/RO water only (ideally). A plugged heater core can also cause a no-heat situation. Just because the hoses are warm doesn't mean you have proper flow through the heater core. The outside passages could be open, and the middle ones plugged.

If you knew someone who had a 'good' scanner, it would be real helpful to get into the HVAC control module and check for HVAC codes. Then perform an HVAC doors sweep test to test the blend door motors and full range actuation. During normal operation, the blend doors cycle and the computer notes when they reach full open and full closed ...so the computer know's the position of the blend doors (ie 30% or 72%). Motors can fail, and so can the hinges of some doors ...or where the motor connects to the door itself. Also, an outside air blend door or motor (to the cabin or the hvac box) failed (or the hinge busted), the heater can still provide heat, but not enough to overcome very cold 'fresh' outside air on a cold day. In other words there 'could' be more cold air entering the cabin entering the cabin than the heater can overcome (making it 'feel' cold inside). Or, if it was like our Jeep when we got it (used), it had multiple blend door issues the previous owner had not addressed ...and was a mess till we got it sorted out. Some of these blend door issues I've outlined may vary depend on the model truck you have (basic or dual-zone hvac). The dual-zone and more complex units tend to have more possible fail points.

Another thing you could do if you suspect a heater core leak, is pry up your pass door's sill plate and put your hand under the carpet (or matt) and feel for wetness under there. That's a pretty good sign of a heater core leak.
I took your advice. Thanks. As a hunch I did the thermostat assembly.
It now does not overheat. And hissing gone. I think what I was hearing was the overflow tank hose.
Im staying around 215-219 degrees.

Also pulled out the glovebox.
My recirc door us up when on heat, and down when on AC. Could it be a clogged heater core even with both hoses hot under hood?
 

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Ryan Poulos

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The fact that you did get heat points to a blend door. A heater core blockage won't come & go. As for the smell, how is the antifreeze level? You can get fluorescent dye at a parts store and add some to the radiator, remove a little antifreeze from radiator to make room ( don't put it in the overflow tank). Drive it a while after engine reaches temp. Any leak will glow under a black light.
Thank you. I cant find a leak anywhere. I was a little low. Im going to drive it today after I did the thermostat. I figured for $100 Id try it. Its now not overheating in my driveway running 28 minutes. But I’ll drive it for a bit.
Heater is still not working and the actuator is working properly.
 

Elvira

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I would say the blend door is non operating. I have fixed them before where they have broken off a little tab that fastens to the actuator leaver. In a pinch, this time of year...just prop open with clothes pin or what ever. You can order the door or part as needed when you decide to fix. This is an educated guess without seeing it, but a good probability.
 
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GTyankee

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First a friendly note:

A motor is powered with electricity
An engine is powered by anything else, ( unless you live in England )
-------------------------------------------------------------------------------
In your Climate Control Unit
You have 4 doors, each run by actuators, actuators are usually interchangeable, ( a Mega Cab has 5 actuators )

Behind the upper glove compartment, there is a Recirculation Door
Below it & slightly to the left of the Fan, there is a Blend Door
Directly in back of the Climate Control Panel, there is a Mode 1 door
Just above where your right ankle would normally rest when driving, there is a Mode 2 door

------------------------------------------------------------------

I would try moving the knobs on the control panel to see what is actually working. A/C, Low, medium, High speeds, heat or cold to the floor, heat or cold to the vents, cold to the defrost.

I would determine which heater hose carries the water into the heater & which is the return line.

Then watch a Youtube video on how to backflush the heater core in the cab, back flushing pushes any debris out the inlet hose, do Not use High Pressure
----------------------------------------------------

Each actuator can be disconnected from the housing ( 2 screws ), & you can watch it cycle once you connect it back into the electrical socket

also once the actuator is detached, you can gently move the metal rod that moves the different doors, you may hear the door as it fully opens or closes.

If you decide to remove the Climate Control Box from under the dash board.
The Mopar Actuators are the quality unit
The different doors, you would want to stay away from the Mopar doors
Many people use the Dorman replacements
Personally, i would spend a bit more & get the ones from https://www.blenddoorusa.com/
If i planned on long term ownership

Grab a beverage of your choice, put your feet up & hopefully learn about your climate control system

 

Ryan Poulos

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If an intake gasket were leaking would I hear the hissing noise? After 3 hours of driving it finally is getting hot again. And hissing is back. Sound front of motor and internal. Not leaking inside or outside. Must be burning internal. No smoke from pipe it smell from pipe. Any ideas???
 

cancunlsp

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I had this same problem last winter. Mine was simple (thank goodness), something had gotten into the blower and had jammed it so it wasnt turning or blowing any air so all the hot air was just sitting in the dash
 

smiley

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2014 Ram 2500 Crew
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6.7L Cummins
First a friendly note:

A motor is powered with electricity
An engine is powered by anything else, ( unless you live in England )
-------------------------------------------------------------------------------
In your Climate Control Unit
You have 4 doors, each run by actuators, actuators are usually interchangeable, ( a Mega Cab has 5 actuators )

Behind the upper glove compartment, there is a Recirculation Door
Below it & slightly to the left of the Fan, there is a Blend Door
Directly in back of the Climate Control Panel, there is a Mode 1 door
Just above where your right ankle would normally rest when driving, there is a Mode 2 door

------------------------------------------------------------------

I would try moving the knobs on the control panel to see what is actually working. A/C, Low, medium, High speeds, heat or cold to the floor, heat or cold to the vents, cold to the defrost.

I would determine which heater hose carries the water into the heater & which is the return line.

Then watch a Youtube video on how to backflush the heater core in the cab, back flushing pushes any debris out the inlet hose, do Not use High Pressure
----------------------------------------------------

Each actuator can be disconnected from the housing ( 2 screws ), & you can watch it cycle once you connect it back into the electrical socket

also once the actuator is detached, you can gently move the metal rod that moves the different doors, you may hear the door as it fully opens or closes.

If you decide to remove the Climate Control Box from under the dash board.
The Mopar Actuators are the quality unit
The different doors, you would want to stay away from the Mopar doors
Many people use the Dorman replacements
Personally, i would spend a bit more & get the ones from https://www.blenddoorusa.com/
If i planned on long term ownership

Grab a beverage of your choice, put your feet up & hopefully learn about your climate control system

Why do they call it motor oil then? I have heard this before when someone said motor vs engine. I didn’t really get it.
 

GTyankee

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Smiley
The only thing that i found is still confusing
Just like the rest of the World uses the Metric System & the USA uses the SAE system, In a decade or 2, the whole world will be Metric.
We call the cover over an engine a Hood, many other countries call it a Bonnet

England & many other countries call a combustion engine a Motor
We call it an engine

WHAT IS THE DIFFERENCE BETWEEN ENGINE OIL AND MOTOR OIL?
There is no difference. Just like how both lawn and yard mean the same thing; both engine oil and motor oil are valid ways of talking about the oil that lubricates your engine.

Another thing, some people have Yard Sales, Tag Sales, Flea Market, Garage Sales, rummage sale. The name seems to change with the part of the country that it is held in.
 
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