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.

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.

thanks! I will look into that

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:



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

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.

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..

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:



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

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!

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

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

all data said there was a issue with resistors so Im getting a new $15.00 also the ground wire on the blower is super small and some of the wire look broke so Im goin to add a new ground wire and see if that helps.

Lots of good info here....Another A/C question, My 1998 dually is on its 3rd OEM compressor and its leaking again (belly leaker) and its out of warranty from the dealer, any good after market one you would recommend.
thanks in advance.

I work at a dealership on the back counter. Iv been using the NAPA ac kit with no issues. It been about 2 years since the first one we did and never had one come back, make sure you get the kit with new compressor.

ok I repair the melted wires in the ac harness and added a thicker ground wire from the blower motor directly to the truck..... no more hot wires and the blower motor blows harder then ever =)

Rockin'...good to hear yours is working right again.

98crewcab - your compressor is a type known for leaking at the seam where the two case halves meet. Very bad about it. Believe it or not I heard from one guy that cleaned the shit out of his and JB-welded it, and so far it has lasted through a whole season. If you're going to replace it, you might check out alternative models that are supposed to be better than the Sanden style, like the Seltec Valeo you can get from ackits.com.

I just fixed up the A/C on my '94 C2500LD, original 16 year old compressor was leaking at the front seal, slowly letting the 134 out but also letting oil out. It used to hold a charge for about a year, or long enough to last through the hot weather, but this time around it lasted maybe 2 months so I said screwit and put in work.

NAPA Cold Temp compressor, accumulator, and orifice tube - lists for like $289 but was $200 at my cost. Wasn't real impressed with the o-rings that came with the accumulator, kind of a loose fit, but they seem to be holding. They amazingly didn't have the o-ring that goes on the line for the orifice; the guy kept trying to give me the little one that actually goes on the orifice itself - a new orifice comes with one already installed so who knows.

Got it sucked down and charged up, cold as ice now, though it kinda bothered me that it tripped into recirculate mode while I idled at a stuck red light in a pack of lemmings for about 10 minutes. Went back to normal after I got moving again for a few seconds...but seemed out of character. It was maybe 93F and 70% or more humidity at the time so Idunno, not an A/C expert. But it makes me doubt the new pressure switch I installed in the back of the compressor.

Richard