Originally Posted by
DieselWins
Hello, Cummins Owner!
Does your HVAC not respond at all, for any reason, with any buttons? Do you have a sunroof? Has it been leaking? Here I will explain from cause to correction, everything to get your beloved HVAC running again.
PROBLEM: HVAC controls do not respond at all, no change in UConnect, no blower motor activity, no DTCs, no trouble lights, nothing. I was not able to find anything about this, and was met with everything from hostility to dismissive disinterest when calling stealerships to seek information. Either none of them knew, or none of them cared. My local stealership quoted me $220 just to change the part that was the culprit.
CAUSE: In 2014-2018 RAM 2500/3500 (that I know of) trucks with a sunroof, there are drains in all 4 corners of the sunroof. The drain that caused my problem was the front passenger. It carries the water from the sunroof track down and along the headliner, down the A pillar, beside the dash, and out through the door jamb in between the hinges. This tube is too small, and brittle. If it comes disconnected, plugs off, or suffers a failure for any number of reasons, probably when you least expect it/at the worst possible time/both, it can cause several issues. These issues include a sucking/gargling noise when accelerating or turning corners, usually after you've been sitting stationary in the rain for a while, or immediately after leaving a car wash. It can leak in, soak your headliner, run down the headliner to get inside the plastic cover of the A pillar, get your airbag wet, leak out the screw holes for the plastic A pillar cover, leak all over down the front of your dash, and leak down the inside of your dash, directly on to and in to your HVAC CONTROL MODULE, Part Number P68366553AA for my 2018 RAM 2500 Laramie Mega Cab. Check with your local stealership for the correct part number for your VIN, as this seems to be a stealership only part, at least for the time being.
FIX: Since I wasn't able to find any videos or resources anywhere about this, I figured I should post here in hopes of saving someone else the trouble that I had. Here's how you fix it. (Prerequisite: Must be -10°F or colder/95°F or higher) First, let's take care of that damn drain tube. Get yourself a piece of weedeater string. This tube is fairly brittle, so don't use wire or something that will break it. For me, I didn't want to screw around in the sunroof, standing all over my leather seats, so I started at the door side and ran the weedeater line up the tube. Once it cleared the top, I vacuumed out the dust and bird turds. I then closed the sunroof and washed the pickup, ensuring that the drain was actually working. Get yourself a wife or a good girlfriend for this, they're well worth the hassle for a second pair of hands. After clearing the tube, it gets easy, and the stress is over. Assuming you're not leaking, you're now ready to replace the HVAC Control Module. Start by pulling your lower glove box, but do not empty it out. Disconnect the damper string and let it go. When you hit the stops, squeeze the top of the sides of the glove box nearest to the dash. You'll be able to see them move and clear the dash itself. Tilt the glovebox toward the floor, spilling part of the contents that you didn't empty out, and gently pull and work, tilting it downward more and spilling more contents, until it lets go and comes free. Set it to the side, in a precarious fashion, ensuring that everything that didn't dump out while removing it does dump out this time. Now you have easy access to the HVAC control module. This actually doesn't give you much trouble. The plug is white plastic on a black module, easy to see, only a single detent piece. Unplug the module. Now for the fun part. Remove the passenger side dash side trim panel. If you're like me, this is black magic. If you don't care, just pry it up with a screwdriver, trim tool, or your wife's best butterknife. You'll be able to see the module at this point. There are two screws, which you only need to loosen enough to slide out of place. You'll understand when you see it. Slide it out of the locking holes, and pull out through the empty lower glovebox hole. Put the new module in, plug in, tighten the screws, replace the panel, cuss about how much the stealership wanted to charge you for a 10 minute/ 1.5 beer job, replace the lower glovebox, let the damper string slip out of your fingers 17 times, cuss more, achieve damper string reconnection, close glovebox, turn on HVAC and bask in the glory that is a properly working RAM HVAC system. If you made it this far, thank you, and you're welcome. I hope it was as good for you as it was for me.
If anyone has questions, feel free to message me. I'm not super active, but I will try to watch and respond to people as best I can. My ADHD may cause interruptions in monitoring.
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