[Ajacobson62396]

I have a 2003 dodge ram SLT that won't blow cold or hot air, the blower fan works like it should at low or high speed. Also the vent location won't change, only blowing out of the front dash vents. Already replaced the HVAC Control moduel. I did notice the blend door actuator door itself was broken sitting on top of the blower fan, and removed it. The actuator moves the gears when changing hot to cold on moduel. Got a new door(no installed yet) but highly doubting this will fix the no heat or ac issue. Anyone have an idea of how to fix this issue. Summer is creeping around the corner and in FL AC is a must.

 

[GTyankee]

Lift the hood & pull the hoses that go to the heater after finding the hose that is hottest.
Then blow low air pressure from a compressor into the hose that was coldest when the truck was warmed up, if you don't have Air, you can use a water hose at Low pressure.
The antifreeze & a bunch of gunk should come out.

Putting it through the cold hose will force the old crap out of the hotter hose, that is called Back Flushing

I suggest having the heater controls ON when you do it, the engine does not have to be running
Disconnect the heater hoses as close to the radiator as possible, doing it at the firewall is sometimes a chore

You can watch this video & get a good idea of what to do, i know that it is not a dodge truck, but the method is the same

I do suggest using a water hose though

 

[Ajacobson62396]

Should this be needed after the engine was just completely rebuilt, you'd think they would have flashed everything out. I did forget to mention when I took apart the blower fan there was so much paper in the fan that got sucked in from the glove department. Not sure if that would matter.

 

[Mopar311]

Just curious, did the problem show itself as soon as you replaced the control module? Or was it before hand? Not sure what control module you have. Does it use nobs or is it electronic? I have had a similar issue in the past, and the problem was with all the vacuum lines that connect to the back of it. Hope that helps.

 

[Ajacobson62396]

It had the issue from the start. I replaced the moduel thinking that was the issue. It is electrical with knobs lol with only 2 connectors connecting it in the back.

 

[Mopar311]

It had the issue from the start. I replaced the moduel thinking that was the issue. It is electrical with knobs lol with only 2 connectors connecting it in the back.

That’s strange. I would listen to the underside of the dash and under the hood and see if you can hear any sign on vacuum leaks as you change the control settings. If the fan works, are you able to change the vent settings like defrost and vent and floor etc? Got to make sure the blend door is actually moving too. I can see how the heater core could be a problem for no heat, but not for no AC. Last but not least, check all the fuses associated with it.