Heater Help!

[Ben Murrie]

Hey Folks,
So due to the help on this forum I've been able to fix several things with my 2002 RAM Quad Cab. I've also used the forum to try to troubleshoot an issue I'm still having, but to no luck. My heater won't blow hot. The A/C works fine, the blower works fine, and I can change the levels okay. It just doesn't get hot in any vent or any setting. The resistor is new, the heater core is getting hot and has been flushed, the blend door functions, the ignition switch is new. Is there any other possible solution I'm missing? Thanks for your help.

 

[Snake15eyes1998]

How is your coolant level? Also, how do you know your heater core is getting hot? Are you feeling the hoses that go into the fire wall? If the fan is working, and you said it was. You also said the heater core is getting hot. When you go from cool to hot. Is that function working? Can you feel a difference in temperature at all?

 

[Ben Murrie]

Coolant level is good. I'm gauging temps by feeling the tubes, and feeling the heater core when taking off the glove box. I'll see if I can feel it when going between hot/cold. Thanks

 

[Nick_rp]

Since heater core is hot and the fan is blowing than, not sure about specific years but the older rams used vacuum to open and close the heater door. Its called the heater control valve i believe. Than they stepped it up to a electronic controller, again i dont know when exactly, somewhere in the 2000s. The controller became integrated into the adjustment knobs.

Thats the last item on the list

 

[Mallardsx2]

Did you ever get to the bottom of this issue? I am also about to pull my hair out with my 2016. Both hoses are hot going to and from the heater core. It is blowing luke warm air. Is there a fuse that controls the door? I checked all of the fuses but I cannot seem to locate a bad fuse.

I dont want to tear the dash apart but it looks like this is what will happen.

Also I should note that I bought my truck brand new and when I looked there was no cabin filter in the truck where it is suppose to be at....

 

[MK82]

So crazy enough, this happened to me too... sorry if this is an old thread...

I just got my 07 3500 and the AC will freeze you out, all the blend doors work as the temp will adjust as you turn the nobs, and it will move through the positions, floor, dash and defrost.... But if I have it on heat, it's luke warm at best. The only time it actually gets warm is if I have it on recirculate. But obviously it's pulling in luke warm air and reheating it so it would naturally be warmer. But it never gets hot. Does anyone have an idea of what this might be?

Thanks,

Matt

 

[GTyankee]

There are 2 hoses that pass through the firewall
normally when your engine is up to operating temp
The Supply hose should be degrees hotter than the Return line

I would mark the lines & disconnect them

Normally you could push Low Air or garden hose low pressure into the Return Line & any gunk would come out of the Supply side. in other words, you are back flushing the system.

There are Youtube videos showing how others have done it
you need to get as much of the gunk out of it as possible

I don't know how safe it is, but some of the videos show them using a strong cleanser, like CLR to help break things free

 

[MK82]

Thanks @GTyankee, I've seen a few videos on the YouTube, so I'll tackle this this weekend.

So this may change things, I went to get groceries this am and had the heat on and I leaned over to get something and noticed the air on the passenger front vents is considerably warmer than the 2 drivers side vents... I remember there was an issue with these trucks that one side would get cooler than the other with the AC. I don't have dual zone so I guess this is just design flaws?

Matt

 

[GTyankee]

I have watched several videos on the HVAC system
This is what i believe they are saying

The Recirculation Door, when open allows fresh air into the cab
when closed, the air in the cab just keeps recycling, no fresh air enters the cab

The MODE Door, is located just to the left of the FAN
There are 2 MODES, Cold & Hot
When the door is in one position, the air passes over the HVAC Heater Box & you get Warmer air
When it is in the other position, air passes over the Condenser & you get Cold air

The 3rd door is a BLEND door
i believe that this door guides the Air flow to Passenger & Driver side FLOOR or when in the other position, the Air Flows to the vents

The 4th Door is also a BLEND Door, it directs the air to either the Floor or Defrost vents near the windshield

The control knobs must have the ability split functions & the speed of the Fan

................................................................................
TRW makes the Actuators for the OEM Mopar Actuators
They are the best Actuators

If one of the 4 doors themselves should break, i advise that you stay away from the OEM DOORS, they are made of cheap brittle plastic

Dorman doors are suppose to be better

Blend Door USA makes aluminum doors
they are much better than the heavy plastic doors

so your budget may be the deciding factor