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Dually Engine \  A/C

A/C

Dually Engine Dually Tech
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lmdguy   +1y
so on my 1995 3500 with 454 I got a new ac compressor, dryer and orifiace, had system flushed and charged to specs. But it doesnt seem to have any volume (doesnt blow hard) blower motor works on all speeds. Or is this normal? Guy at work has the same year truck but 2500 series and says his is the same.. should I consider replace the evaporater??
thanks for any info.
brianbgboy   +1y
the servos that control fresh air to recirculate air stick in these things a lot. when they do, it wont blow hard at all. make sure the air is only coming out if the vents not the floor or defrost vents. if the evaporator isnt leaking freon, i wouldnt change it.
lmdguy   +1y



thanks! I will look into that
someotherguy   +1y
They also tend to get totally clogged in crap, and it's difficult to effectively clean it without complete disassembly. You can get to some of it by removing the blower fan and carefully digging out any loose stuff; there will be a temptation to spray something in there but then it's gonna go through the evap and be inside your air box. Also, strong possibility anything that goes through will then just fall down on the heater core. The evap stands upright, and just after it in the air path is the heater core, laying sideways.

Note not just the leaves/pine needles but the muddy-looking muck clogging the fins:

thread post photo


ALL air in the system must go through the evaporator core, regardless of control settings, so blockage here is the one thing that can cut down airflow in all modes.

Richard
Post was last edited on Dec 22, 2011 08:12. This post has been edited 1 times.
lmdguy   +1y
ok I checked it the other afternoon and there is air coming out of the floor vents when I have it set to the dash vents. so should I change the servo? I still need to try and clean the Evap.
lmdguy   +1y
too top it off I get to work this morning to findout my dually has been broken into and they stole my ac control head =( i guess with a retail price of $212.00 i could see why..
someotherguy   +1y
Man, WTF. People suck ass...

You can find that control unit new for around $160 if you shop a little. I'd avoid buying a used one unless they will let you try it on the spot to be sure it works, these are very commonly bad, and also frequently get damaged when someone removes the factory stereo and lets the antenna lead fall down onto the unprotected circuit board. And, the plastic these are made out of is like glass, so look closely for damaged tabs that hold it into the dash and also hold the gray connector on at the end.

OK, once you replace the A/C control...back to the vent position, most likely cause is gummed up linkages on the actuator. This is the one at the far left of the A/C box, just above the driver's side of the transmission hump:

thread post photo


Lay some newspaper down on your carpet to protect it, wash down the linkages with WD40, work them back and forth a little. You'll see that the flat metal parts are actually sliders. The factory lube gunks up and they quit working right. After that WD40 dissipates a bit, a small amount of white lithium grease might be a good addition.

Richard
Post was last edited on Dec 27, 2011 01:12. This post has been edited 1 times.
lmdguy   +1y
YA it sucked. Im lucky as I work at a dodge dealership and my friend hooked me up at employee cost. Thank you for the pic Richard I will mess with it tonight and let you knw!
lmdguy   +1y
quick update: I checked that actuator and it was working fine, but still cleaned it and lubed it. I kept looking around and decided to pull blower motor to check evap, it was pretty clean maybe even changed a few year ago . But I noticed the fresh air door was open half way, ran some test and it didnt move no matter what setting. So I adjusted it to be in reserc at all times now ac is much colder! But also found blower motor wires are getting super hot
someotherguy   +1y
Did the airflow problem between floor/dash get corrected? The actuator working is one part of the picture, the sliders being able to work is the other. If it began working properly without you having to do anything, then the A/C control that got stolen was probably bad.

On to the fresh air/recirc door actuator - it goes bad way more often than the other two. It's kind of a PITA to replace but can be done in about an hour with just a few simple tools. I posted a writeup on ChevyTalk and FullsizeChevy that I could repost here if you want.

Blower motor wires getting really hot means you've got bad connections, or blower motor is going bad and drawing more current than it should. That's bad on the wiring, blower motor resistor, fan switch, and fan switch connector.

Richard