BuzzardKing

New to the forum.

I have an issue I can't figure out and have searched forums for answers with no luck. I have a 2011 Crew Cab 2500. When I turn on the fan, I can feel cold air on my hands in addition to the warm air coming out of the vents. When the fan is off, I don't feel any cold air. Doesn't matter how high/low the fan is set, or which vent it is set to come out of. The truck is at 185 degrees and hot air comes out of the vents, but my hands get colder. Thinking back, I would feel hot air in the summertime, but I just thought it was because I have a black truck. Doesn't matter if it is on recirculate or not. Could it be one of the doors behind the dash is not fully opening/closing and letting outside cold air come in without going across the heater core? What does the blend door actually blend? Could it be hanging open slightly and allowing cold air to come in around it? Would I notice anything else to help narrow it down? Any suggestions on where to start would be greatly appreciated.

FMB

The Blend Door takes the incoming stream of air from either the cabin (recirc mode) or from outside and slips some to all of it through your heater core. From there it goes to your vents. If your Blend Door is not operating correctly, it may be directing only a portion of the air through the heater core and more air may be diverting around it.

If you put your heater on full hot, and hot air isn't coming out (lots of cold air coming too), I would suspect the Blend Door may be broken. What most folks here have done to repair the door is use a replacement door from Heater Treater. You can view videos on their site to help troubleshoot and replace doors.
Welcome to DTR. Back to morning brew . . .

BuzzardKing

Thanks. I will pull the dash and see if the door is broken.

Busboy

I see you are deleted which means the cooling system has been open. The top of the heater core is the highest point in the system so it's possible to get air trapped in part of it. All the air coming out the vents first passes through the evaporator core and will be cooled if the compressor is running, don't forget it runs in DEF mode as well. This cold air even if routed through the heater core will still be cool if there is air in part of the heater core. The 2010 and up trucks have a different HVAC plenum than the 2002/2009 ones did and I don't remember reading of anyone having door problems so far.

BuzzardKing

I just deleted the exhaust side and didn't touch the EGR. Would it still be possible for air to be trapped in the heater core?

Busboy

I doubt it if the cooling system has never been opened but I would certainly try bleeding the system at the stand pipe on the passenger side of the engine and should you get any air out there then air in the heater core would be possible. You might also try a reset on the entire HVAC system by cycling the M11 fuse in the PDC under the hood drivers side.