another A/C issue

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Yarek

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I got the truck earlier this summer (2001, 2500, V10) and the A/C was intermittent, and to be honest, it would only blow cold for a few minutes and then quit completely.

I took it to a shop and they evacuated the system, put fresh refrigerant in and even checked to make sure there aren't any leaks. All checked out and the AC worked again! for not too long...

Took it on a little road trip and after a while the A/C would quit when I had to floor it on some uphills or under heavy acceleration. But it would come back on.

Recently it went back to square 1: it works for a bit and then quits forever.

Another issue I noticed is that the cruise control isn't very responsive in hilly terrain, meaning: it will let the truck slow down quite a bit on uphill runs, or let it roll quite a bit over the setpoint on descends. Which leads me to thinking that maybe there is a vacuum leak somewhere? I really don't know where to start the diagnosis.

Lastly: it is a 4 speed A/T and it sure feels like the truck doesn't like being in the 3rd gear. It skips quite quickly from 2nd to 4th and only in some situations it settles down on 3rd when I have to floor it on steep climbs. No rattle or anything, it just kinda skips through the 3rd relatively quickly, staying on 3rd for maybe 1-1.5 seconds. The transmission fluid seems relatively fresh. Still has some of the reddish color to it.

The truck doesn't make any weird noises. It has plenty of go, doing a great job pulling an RV trailer through the mountains last weekend. Not even sure these three issues are related, but they might be? The cruise control is a non-issue really; the 3rd gear thing: not too worried about it, either, but the AC not working reliably is an issue. Summers are hot here. And so are springs and falls ;-)
 

RodeoRam

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On the A/C, when you say it quits completely, what do you mean? Does the fan stop blowing, or does it blow non-cooled air? If the fan stops, it could be the resistor block on your fan or the fan itself. If it is blowing warm air, it could be the blend door and/or actuator. I had to replace all of those on mine at one time or another.

Another A/C issue I had on my '01 was that with the A/C on, the output would switch from the dash vents to the defrost vents when I pressed the skinny pedal more. When I let off, the air would switch back to the dash vents. IIRC, that was a check valve in the vacuum system. I think it was near the top of the firewall. You could probably google it to find out.

Your uphill cruise issue could also be vacuum related, but then again, it might just be poor design/programming. Again, IIRC the 2nd gens had the vacuum line for the cruise running under the battery. Acid from the battery would eventually eat into the line causing a vacuum leak. I'm thinking that it's a physics or programming thing, though. When starting up a grade in overdrive with the cruise engaged, it is on the wrong side of the horsepower/torque curves, and the cruise/transmission take too long to react causing a big loss of speed. Try turning the O/D off before you start up the hill to see if it improves. On the downhill side, remember this is a 2nd gen before they incorporated downshifting and engine braking into the cruise control to keep the speed near the set point. As long as it was safe, I loved to see that MPG indicator peg on 99 as long as possible.
 
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Yarek

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On the A/C, when you say it quits completely, what do you mean? Does the fan stop blowing, or does it blow non-cooled air? If the fan stops, it could be the resistor block on your fan or the fan itself. If it is blowing warm air, it could be the blend door and/or actuator. I had to replace all of those on mine at one time or another.
Another A/C issue I had on my '01 was that with the A/C on, the output would switch from the dash vents to the defrost vents when I pressed the skinny pedal more. When I let off, the air would switch back to the dash vents. IIRC, that was a check valve in the vacuum system. I think it was near the top of the firewall. You could probably google it to find out.

Thanks for the reply. Yeah, the fan stays on, it just starts blowing a relatively warm air, possibly warmer than the outside air. It definitely does it when I floor it, and it just does it on its own after it's on for a while. Also: it keeps blowing the air through the dash vents, it just turns pretty warm quickly.

I read somewhere about the vacuum line under the battery. I'll look there first when I get a break.
 

crash68

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You need to figure out if it's the AC system or a blend door(s) that causing the issue. I've read some year trucks had issues with the vacuum line going into the cab to HVAC controls cracking causing issues.
If you notice that AC blowing warm, check the larger of the two line going to the compressor if it's cold, if so your problem is probably with the blend doors.
 

PaPitt

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iS YOURS A DIESEL OR GAS Truck .
I worked as a service advisor from 99 too 2007 i believe . I should remember your shifting issue .. But I'm going to say take it to a quality trans shop & I'M Going to saythey can fix that . I'm thinking it need a complete fluid & replace the filter with only a Chrysler filter .
If shop insist on using theirs of pdq parts. THEN Ask them if it doesn't fix it will the do it over & Use a CHRYSLER FILTER . yOU MAY have to take them the filter .
I over saw about 4 trans techs & they convinced me after about 2 year that the chrysler filter was better . . But a fluid change & replace the Transducer & Governor pressure Solenoid ..
.. Oh & the org pan gasket is a reusable gasket . If it has to be replaced it cost about $40.00. But it's good.
 

PaPitt

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I might ask if your trans has an issue of up & down shifting at 42 MPH IN & OUT OF 3 & 4TH GEAR .
iF SO THERE is a battery cable on the passisde THAT has about 2 or 3 cables & they get corroded . We sometimes cut the plug joint out & SOLDIERED ALL the cables back together . & THEN RECOVERED with heat shrink tubing ..
I was the hero when I found that repair .
 
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Yarek

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I haven't really needed the AC a whole lot, and it kinda-worked, but recently it quit. So finally I carved out some time yesterday and inspected the vacuum hoses. They seem to be just fine. Old, but seem fine. Next, I went behind the glove box compartment and found that the vacuum-operated actuator of the flap that regulates whether the air is taken from outside or circulated internally, was detached from the actuator. Short of taking it all apart there was no easy way to screw it back on, but I managed. So the flap opens and closes properly again. I found no obvious issues until... I ran the truck while parked, with the AC on and I popped the hood open.

The cold line was getting a little cold, and the hot line was getting warm, so far so good. But I noticed that the clutch on the AC compressor kept disengaging the compressor constantly. Here is a 15s clip:

Any suggestions on what the fix is?
 

Daw14

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The compressor is made to cycle off and on , it is most likely operating as it was originally designed.
 
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Yarek

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understood, but I'd like it to blow cold air inside :) it's barely a little cooler than outside air.

@Streettrucking785 commented on the video that the system may be low on refrigerant. I'll try to check that, but 3.5 years ago I had the system recharged and checked for leaks. It did work for a little while, but would always quit under heavy acceleration, which led into this discussion about vacuum leaks. I can't hear any hissing or anything that would indicate an issue.

If it really is low on refrigerant, I'll see what I can do about that... I drive this truck <2k miles a year and really don't want to dump more money into it than I have to. I can continue without the AC, but it sucks during a heatwave like now...
 

Tray Burge

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Sounds like you have a leak that needs to be found, all the refrigerant in the world won't help if it's leaking out.
03 here and you can literally hang meat inside when it's 100 degrees outside.
 
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