Fixed the air in the Mega Cab

[firefighter_2000]

Finally had a couple of nice cool days this past week and fixed the mega cab. I actually have some nice cool air and it blows VERY well now.

A HUGE thanks goes out to Scbroder & to Kry226 for their posts concerning the HVAC system. I printed out both step by step processes & was able to complete the job with little difficulty.



Scbroder's post is here:

https://www.turbodieselregister.com...ussions-faq/176307-hvac-removal-pictures.html



Kry226's post is here:

https://www.turbodieselregister.com...93-hvac-heater-treater-doors-replacement.html





Had three of my doors broken. The recirc door was broken at both ends of the axle shaft and was laying on top of the fan, so there wasn't much air being flowed. The blend door was broken at the shaft as was mode 1 door. I bought the mode 2 door as well but ended up not using it since heater treater doesnt take into account the mega cab on those trucks. The mega actually has another set of "doors" that are couple via rod/cam setup to the mode 2 door. The second set of doors is probably 3"x3" each (two of them) and open/close at the same time as the mode two door and controls the air flow to the REAR vents. The motor that opens/closes mode 2 door is set on a set of "towers" that holds the motor away from the box to allow the cam & rod to travel underneath it to open/close the doors. Neither the mode 2 or the doors to the rear air appeared to have any wear to them either. I wasn't completely satisfied with Heater Treater either. I emailed them and asked them to contact me asap so I could figure out what needed to be done. Two days after I emailed them (and decided to just put it all back together without their mode 2 door) they replied and said they didnt have enough of a market for the one like I have (the mega cabs) and that I should just wedge the doors to the rear vents open and cut the "towers" down so that the motor will engage with the end of the mode 2 door. SO... Heater Treater Doors: AWESOME... Heater Treater Customer Service: SUCKS.

I also cut the screen out of the top that everone reccommends. That worked well too.

I also added a couple of 3/4" ball valves to the heater core lines.

Dont forget to have a set of the a/c line disconnect tools handy when you start too.

Be VERY careful when you're taking the bolts out of the top of the dash (specifically the two 10mm bolts) and DONT crack the windshield... Like I did. Lucky for me I have comprehensive on my insurance!



If anyone has any questions feel free to email me at firefighter_2000 AT hotmail DOT com, or just reply here. Will do my best.

Craig

 

[ColemanR]

How long did it take you and on a scale of 1 to 10 how tuff? Thanks Randy

 

[firefighter_2000]

I kept having interruptions (phone calls, rescue calls, trip to the parts store, lunch and/or snack run etc. ) but actual time spent was probably 4-6 hours nor including recharge of the system. It wasn't a bad job at all and is definitely worth the time and effort!
Craig

 

[ColemanR]

Thanks I guess I just need to step up and getr done LOL

 

[firefighter_2000]

Dont forget

Dont forget the a/c line disconnect tool. I didnt have one when I started. Luckily a friend of mine had one and brought it to me. This is the set I barrowed.



#ad




Everything else is basically just metric hand tools. I also found it easier to remove the air box & intake tube to the turbo, along with the battery and the coolant reservoir.



Craig

 

[Crunch]

Can you rank the doors you replaced on either ease or difficulty? I've read that the recirc door is the easiest, but what about the blend door and Mode Door 1? I guess you should be glad you didn't need to replace Mode Door 2, as Heater Treater says that's the most difficult. Also, why did you evacuate your system? HT also claims that there is no need to do so when replacing the doors.

 

[firefighter_2000]

Im going to quote Kry226 on this:



The Heater Treater folks really put a premium on not pulling the dash, and have designed their instructions (which, by the way, are very thorough, in addition to their installation videos on their website) for the installer to cut into the HVAC box and cut some of the metal frame behind the ash tray/cup holder area in the dash for the R&R of a couple of the HVAC doors. That may be a good alternative for some folks, but I am one of those ISTJ types (Myers-Briggs personality indicator), and cutting into the box just doesn’t “cut it” for me. IMHO, the only way to do this right, is complete disassemble/reassemble. Pics follow their descriptions.



Im with him on this one. I dont want to just cut holes in the HVAC box and feel that the best way is to actually remove the HVAC box from the truck. It IS much more time consuming and requires removal of the HVAC box, but I feel its better to do it this way. I will look & see if I still have the instructions from heater treater, and if I do I will scan & post them for everyone to see here.



Craig

 

[Kry226]

Great, Craig! So glad you got it done and sorry I didn't get back to you as quickly as you needed. From the sounds of it, I don't think I would have been much help with the megacab nuances anyway.



Anyway, enjoy your new coolness!

 

[Crunch]

Im going to quote Kry226 on this:



The Heater Treater folks really put a premium on not pulling the dash, and have designed their instructions (which, by the way, are very thorough, in addition to their installation videos on their website) for the installer to cut into the HVAC box and cut some of the metal frame behind the ash tray/cup holder area in the dash for the R&R of a couple of the HVAC doors. That may be a good alternative for some folks, but I am one of those ISTJ types (Myers-Briggs personality indicator), and cutting into the box just doesn’t “cut it” for me. IMHO, the only way to do this right, is complete disassemble/reassemble. Pics follow their descriptions.



Im with him on this one. I dont want to just cut holes in the HVAC box and feel that the best way is to actually remove the HVAC box from the truck. It IS much more time consuming and requires removal of the HVAC box, but I feel its better to do it this way. I will look & see if I still have the instructions from heater treater, and if I do I will scan & post them for everyone to see here

In general, I agree with you completely. I've gone to great lengths to make sure anything I've added to the truck is a fully integrated install and looks like the truck was built that way. But with 188,000+ miles on the truck I would really have to think this one through before I made a decision. On the one hand, you are 100% correct in your reasoning. On the other hand, I've never done any HVAC work and while mechanically inclined, I'm not sure I would trust my abilities to yank the HVAC box. For those reasons I would be tempted to take the HT shortcut route. Were you able to do the entire job from the cab side, or did you have to do a significant part of it from the engine side of the firewall? Given your time of 4-6 hours I would have to say that pushes me toward doing the same thing you did. That amount of time really seems minimal.

 

[firefighter_2000]

Np

No problem Kry, the rest of your post was a huge help in getting me going. Crunch, if you're mechanically inclined at all you should do this. I'm only moderately inclined and didn't have much trouble at all. The only thing I had help with was recharging the system. If I had the stuff to pull the vacuum and put the freon in, I could have done it all myself. Print off both sets of instructions and get it done! Easy job!

Craig



Another note... I've seen lots of complaints about the mega cab air problems and I would be curious to see how many were actually door problems. It was 99 here today and I couldn't run the ac in the mega on high for long at all.

 

[BGlidewell]

I used scbroder's thread to do my recirculation door last summer. It saved me 100s of dollars and a lot of time. The last step was "different" for my truck and I had to do some head scratching to get the dash pulled back but the whole operation was done in a morning with very little cursing needed.

 

[sevobuck]

I have to agree with firefighter 2000, the best way to do this is with the box out of the truck. Luckily, I was fortunate enough to have this done at a Dealership on their dime. I was able to "help" the tech with the install of the doors. The HeaterTreaters are a solid product but there is room for improvement on the actual fit of the product. I didn't care for the amount of play that there was at the point were the rod connected to the door. With a little bit of ingenuity this problem is easily overcome though. I also cut the screen out and was able to feel a difference in airflow.

 

[MSavre]

Craig,
Did you ever find a part number for the defrost/ floor heat door from Dodge? Or is there a way to make the Heater treater door work with modifications? I'm just about to pull my heater box out, and Dodge Dealer can't find the part in his computer.

 

[firefighter_2000]

Nope, sorry. I never did anything else with it. The only problem I've had, is I have to alternate regularly between defrost and cab heat at certain temps or the windshield fogs over. I've checked and no heater core leaks... I'm thinking there's something with one of the doors not closing completely. I've thought of sealing the recirc door shut so that it recirculates no matter what. See if that helps.
Sorry I couldn't be more help!
Craig

 

[MLee]

Unless the defrost instructions have changed, what are your settings to defrost the windows?

It has been in the past to set the defrost max to the windshield, outside air, setting, with the compressor on to evacuate the moist air. With the windshield setting on, the compressor should automaticly come on. But its important to have the outside air coming in, and not the re-circulating inside air.

Most people don't do this and use the inside air and it just recirculates the moist air, and foggs the windows. OR crack a wndow--(outside air) Makes sence.

 

[firefighter_2000]

I'm not sure I'm following there. When driving, with the heat on recirculate (at any fan speed), the windows will begin to fog over. I'll have to frequently switch over to defrost to keep the windows clear, and at some temps it has to stay on defrost.
Something else I've noticed (forgot about this until this morning) is the temperature of the heated air coming from the vents only gets hot when in the two recirculate positions (face & face/feet). When in the non recirculate (face, feet, & face/feet) positions it only gets marginally warm.
I really need to look further into this.
Any ideas?
Craig

 

[MSavre]

Craig,
My first thought is that you are having problems with the heater core doors (4) that cover it, or the dash controls. Somebody wrote a thread about having to replace dash controls. No matter what position you have the Fan, or Mode (face/feet/or defrost) postion in, if the temp. is up on high you should get roasted out. I'm going to try to remove my unit today to get a better idea.

Mark

 

[firefighter_2000]

I can get roasted out when on recirculate, but the center three positions don't get hot at all.

 

[kuss]

I also have a 2006 mega cab and the dash is sticking somewhere near the top... around the passenger side airbag doors? Do you remember any problems with that? Thanks!

 

[firefighter_2000]

I don't recall.