2003 Ram 1500..... No Heat

[KGrant44289]

I have a 2003 Ram 1500 4wd. Recently the water pump was replaced and post replacement I have no heat. Fan blows but its always cold, Ive burped the radiator and all the air is out, Past that im not sure what to do. The fan seems strong, when I change from cold to heat i dont hear a change occuring. I was told before i bought the truck the Blend door had been removed but havent verified and dont know how to. Its getting COLD.... Please Help. Thanks in advance.

 

[Karlsweg]

Did you change the thermostat? Try flushing heater core?

 

[KGrant44289]

I have not, How would one flush the heater core?

 

[Karlsweg]

 

[KGrant44289]

OK, Thanks. Do these trucks have a Heater control valve? If So how often are these the problem?

 

[Bloody_Knuckles]

99% chance it is your blend doors. There is a well known defect with the plastic on all the doors gets brittle with age and they break at the servo pin. 4 out of 5 were broken in my airbox. There are two of them that direct air flow through the heater core or divert it around them, one for the defrost, one for mode selection, and one for the recirc. Don't worry about trying to index them after you repair them. They'll do it automatically.

It is a PITA to repair. You can do it with a helper to move the dash but count on it taking the whole weekend. The special tools you will need are a set of AC coupler disconnect tools, https://www.amazon.com/gp/product/B0002SRCK6/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1 and an AC vacuum pump and a set of AC gauges. You can borrow the pump and gauges from O'reilly's. Get refrigerant with oil in it because you'll lose a little when you evacuate the AC system. You'll need two cans, one with oil and one without.

Buy the whole set of blend. mode, and recirc doors. https://www.blenddoorusa.com/collections/3rd-gen-02-09-dodge-ram-truck because you don't want to do this twice. Youtube has several good how to videos on it. If the Blend door USA price is too steep, you can find them cheaper, but I sent back 3 doors I got from Dorman via Amazon because one wasn't the right part, the second shaft was bent, and the third shaft had a crack in it. Go OEM or Blend door USA.

 

[SYKRAMMAN]

I second that motion of it being the mode/blend doors. I had to do that job on my old 02, yes it is a pita but can be done in less than a day by yourself, just need the right tools. It's definitely not a cheap repair but still cheaper than having a shop do it. I suggest blendoorusa also, or oe, all the rest are junk and heater treater is a hack job. Like stated above, watch the YouTube vids and you will be able to do it.

 

[HemiLonestar]

I was told before i bought the truck the Blend door had been removed

This, and you have your answer. You'd hear it move if it was still there. No blend door, either all outside air or all inside air (if you still have your recirc door) but no heat added.