Bark

Once again, thanks for the great write up!

Jeff_032500_WI

Just for future searches, here's a link to a thread about the AC Evaporator sensor relocation: https://www.dieseltruckresource.com/...d.php?t=210491 I don't have enough time on the relocation to tell if it works ok, but for now the AIR blows cold after the freon recharge. Jeff

Jeff in TD

OK, I've got a question...

From looking up into the HVAC by removing the blower, I can see there's a screen on the Fresh Air part of the intake.

Is there a way to get that screen out without removing the HVAC assembly? I've tried removing the grille on the cowl vent...

Nathan

I noticed on my truck in my sig today after I recharged my cooling system that I was getting much colder air on the driver side vents than on the passenger. What would be the particular problem I'm having?

BluesCuda

Sorry for bringing up an old post, but I was referred to this particular one from another source. (www.moparts.com)

Anyway, I was hoping to get some advice. I have a '04 CTD that has recently had the mode door replaced due to not having any defrost or floor vent capabilities. I had the dealer replace the heater core and evaporator right away since they were in there. I got the truck back yesterday and the first thing I noticed is that I can really hear a lot more engine compartment noise while sitting inside the truck at both idle and driving down the road. (The diesel clatter and turbo spooling up is much more apparent.) Do you think the dealer tech forgot to install a seal or gasket between the hvac stuff and the firewall while putting this thing back together? (Or something to that effect?)

Any feedback would be appreciated.

(I'm an old school Mopar guy, so my knowledge of the newer cars and trucks is limited.)

Scott
St. Louis, MO

TedT

Not long ago I was looking at the flap motors that can be seen by looking under the dash or by looking through the glove box door opening. I noticed that unlike the other motors, the one on the recirc. door only has two wires. The others have more than two wires. This tells me that the ones with more than two wires feed back their position to the control unit this would allow the the motor to shut down at the end of it's travel once the position is learned. The recirc. flap with it's two wire motor can't report it's position so it must just run the flap to the stop and stall. I think this is why the recirc. doors tend to break more than the others. I wounder if it would help to add a resistor in series with the motor to cut it's torque. Anyone try this?
Ted

Jeff in TD

I don't know if a resister would work or not. I would guess the recirculation motor only having two wires might be due to it either being opened or closed (where the blend doors are variable within their range).

As for the increase in engine noise, the intake for the HVAC is above the glovebox, and draws air from the grille at the base of the windshield.

I wonder if one of the AC or heater hoses might be tighter or routed differently, transmitting more vibration?

BluesCuda

I think I might have found the reason behind the increase in engine noise. I'll need somebody to look under their hood to verify for me though.

Should there be a gasket or seal between the hvac assembly and the firewall? Please see the attached picture. ( I can see the actual body of the hvac assembly from the engine compartment. It seems to me there should be a seal or gasket there.)

Jeff in TD

I just went out to my truck...

I can't tell in your photo, but on mine if you poke your finger in there between the lines, there appears to be a piece of spongy foam...

BluesCuda

OK...that's what I wanted to hear. I can see the actual plastic hvac box from the engine compartment...no foam or anything like that in this area on my truck. (I can see an air gap between the firewall and hvac box as well.)

Thanks for checking for me. I really appreciate it.

I actually just went out and stuffed some blue shop towels in that area in question. I'll find out in the morning if it's any quieter inside the interior when I leave for work.

Jeff in TD

Yeah, no gap between the black foam and the dash. They musta forgot to put the foam piece back.

BluesCuda

That's definitely the problem. The increased interior noise is gone with the towels stuck into the area where the foam gasket/seal should be.

I guess that means the dealer has to tear the truck down again to get the seal on though.

RHC

Jeff 032500 WI, when you ran the servo motors with the new flaps and was watching it operate, did you notice any thing that might have caused the coupling damage? Did the flaps move smoothly or eratic?

See my post : https://www.dieseltruckresource.com/...d.php?t=230765

dodgeramer

great write up very informational have one question .... what does the heater core look like is it the aluminum looking part with fins on it ?