1st post but have been lurking for years.

Noticed a few days ago that the heater on my 2011 Ram 3500 4x4 hasn't been blowing as hot as it usually does.
It's been around -8 degrees for the past few days, super fine powdery snow.
Going home from work yesterday evening a clump of snow blew off my hood onto the windshield and the windshield immediately fogged completely up!
It finally cleared off after a few miles of driving.

This morning at 4:30 am I fired the truck up to get it warmed up before taking off for work. Defrost on, fan on max. Truck had been plugged in all night.
Hop in it 20 minutes later and it's still blowing ice cold air!
Engine temp gauge was showing 190 degrees!
Drove the 10 miles to work at -4 degrees outside temp, with the damn heater still blowing cold air! Engine temp gauge was reading 200 degrees.

I'm gonna pull the damn thing in my shop when I get home tonight and check Antifreeze level and radiator/ heater core hose temps, fuses and whatever..
I'm the original owner with only 35k original miles on the damn thing!

Anyone have any ideas?

Thanks in advance!

 

Low on coolant, clogged heater core, or blend door malfunction. The engine is getting up to temp..... so, can rule out the thermostat.

 

The actuators and blend doors are a weak link in the heating and cooling system.Your issue sounds like a door is not moving correctly. These motors have no stops and are told to turn till they find resistance, then kick out. If the door is broken the motor will constantly turn and the door will stay in one position. If you're trying to get heat and the door is shutting off the flow, it can not be achieved. My guess is that you have an actuator or broken door issue. The 4th gen heater box must be taken out of the truck because there is a 1/8" membrane between the two halves of the heater box. This will not allow you to cut the front of the box apart to simply change the door or doors. All the doors are going to fail at some point so if you're going to fix one you should fix them all so you never have to do the job again.


Jim
BlendDoorUSA.com

 

Thanks everyone for the replies.
I did some internet searching during my lunch break yesterday and found tons of useful info on the blowing cold air issue.
Found one possible fix that I could do at work.
20 minutes before I got off shift I tried the above fix.
I could hear actuators moving during the calibration.
No knocking , all sounded good.
I fired up the truck and set the dial to floor heat.
Left the truck running to warm up, not expecting any change.
After I got off shift I walked to my truck and noticed the snow that was falling had melted on my windshield and side windows!
Opened the door, surprised that I now had heat! Tested all the different zones and had heat through them all!
Was a nice warm ride all the way home!
I’ll be checking coolant levels today and hoping this quick fix solved the problem.