Hey guys/gals.... I have a 02 ram rcsb 4.7 with 178kms... I DONT have climate control and i have a lil problem. I only have heat on passenger side, driver side blows cold and the passenger side blows HOT. figure that one out... maybe the flap after the heater core is slightly closed????

 

Have an '05 and my heater door? broke before, only had defrost.... kept the window clear but frooze my butt off!

 

I think im going to have to rip the lower part of the dash out and see whats up.

 

Did you figure out which door is not working. have the exact same problem. I know you have to take out the dash to get to the unit to fix.

 

I had this same problem on my 2002 ram 1500 4.7. I back flushed the heater core and it started working great. Try that before you rip apart the dash looking for a broken blend door. The heater core gets clogged and the side of the core heating the drivers side isn't getting any flow through it.

My problem now is that with the cold weather I have to keep the heater on max full fan to get the cab warmed up and it takes forever to do it. Any of the other settings can't keep up with the cold outside air mixing with the heater.

 

Do you mean that the heater core outlet splits in half? One side for the driver and one side for the passenger?

 

Holy old thread. I'm not sure how to describe it. The core is like a radiator with an inlet and an outlet on either side. There are 2 tanks that go down each side and then it flows from one side to the other like a full sized radiator.

The HVAC system is designed with 2 zones. If you have the option it might have dual zone controls that let you adjust the temps for the driver and passenger side independently. Half of the heater core provides heat for the passenger side and the other heats the drivers. If your system isn't setup for dual control the door just opens and closes for both sides equally. The symptoms that happen are no heat out of the drivers side with decent heat out of the passenger side.

I replaced the heater core and my symptoms went away but returned within a month. I have had the problem ever since then and still have the truck. I am convinced that the problem is an air lock of some sort in the heater core itself. I can flush the core out with water and hook everything back up and the heat will blow great out of both sides and over the next 2 weeks it will gradually stop blowing hot out of the drivers side. I can repeat the process and the heat will start blowing again and gradually go away. I do not have a dual zone system and my blend door is not broken. I have given up on it and just deal with the lack of heat in the winter.

 

I backflushed my heater core by taking the 2 hoses off the heater core at the fire wall and running water with a garden hose through both holes on the heater core several times and i got heat back on the driver side. Your problem may be that you have rust or something in your cooling system and need a aggresive flush of the system. I used the prestone complete flush and cleaner of the cooling system. I drained the system and poured 2 bottles of the prestone cleaner into my system and drove around normally for about 3 days to completely clean the system and i am satisfied with the heat in my truck. 03' Dodge Ram 1500 4.7liter

 

When you back flushed did you feel any pressure build up before releasing? When I flush my core with the garden hose or even the tool that uses water and air there is no initial back pressure felt as you do with a clogged or partially clogged heater core. The fluid always comes out clean too. There is no rust or particulate from the flushing of the core.

When my problem started and before I replaced the core I used the prestone cleaner too. I've also had my entire system emptied out due to replacing a head gasket.

 

No i didnt feel any pressure build up. When i backflushed it, it was like the heater core wasnt clog up or nothing, i got not gunk or anything came out of the core when i backflushed it. But it started blowing hot on the driver side after i finished. What a mystery.