A/C not working in the CAB

Tiny
BATSIBF
  • MEMBER
  • 1997 DODGE DAKOTA
  • 3.5L
  • V6
  • 2WD
  • MANUAL
  • 140,000 MILES
Bought the truck a month ago for my son, was told the A/C worked. It has never worked for us. So I checked the charge and it goo, the compressor runs (lines in the engine bay are cold and sweating). There is not cold air coming through the vents, I checked the vacuum coming in to the switch and the out of the switch all looks good. I'm not sure where else to go with this except remove the dash and see what is moving and not moving. The fan blows out of each vent selection and the heat works when turned to heat.
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Wednesday, May 19th, 2021 AT 9:26 AM

20 Replies

Tiny
STEVE W.
  • EXPERT
From your description it sounds like a stuck blend door. The mode selector sounds like it's okay as you can send air out the floor, dash and defrost. The cold lines should mean the actual A/C system is working, you just are not getting the cold air through the HVAC doors. On that truck it should be a manual cable control for hot and cold. However it isn't fun to get at the cable on the door end, you have to remove the dash to get to the clip that holds the cable to the door crank.
However you might want to pull the heater control out first just to make sure that the cable didn't fail on that end first. To do that you remove the dash trim then the 4 screws that hold the control in place. Then pull the control out and you should see the clip that holds the cable in place. Try moving the control and see if the cable moves. If it does the other end has either broken or more common it has slid in the clip.
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Wednesday, May 19th, 2021 AT 9:53 AM
Tiny
BATSIBF
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Great that is what I was wondering, the heat does work, it just not getting cold and I already pulled the control unit to make sure the vacuum was working there. I guess a full day tomorrow pulling the dash out.
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Wednesday, May 19th, 2021 AT 10:11 AM
Tiny
STEVE W.
  • EXPERT
Wish it was something easier. While you have it out you may want to look at the vacuum lines for replacement if they show rubber rot. I would also look at the seals on the HVAC module and check the cores for any issues.
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Wednesday, May 19th, 2021 AT 3:28 PM
Tiny
BATSIBF
  • MEMBER
One question, I m in the middle of taking out the dash to get at the valve. I decided to pull on the blend cable, I can hear the door shifting in both directions, is there two doors?
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Thursday, May 20th, 2021 AT 9:08 AM
Tiny
BATSIBF
  • MEMBER
Well, got it to where I can see the blend control.
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Thursday, May 20th, 2021 AT 10:00 AM
Tiny
STEVE W.
  • EXPERT
Only one door. Hard to see in the images but it looks like the lever is moving, if that is the case but you still don't get cold air then it may be the door itself is bad or something got in between the door and evaporator and is blocking the airflow. That would mean you need to open the HVAC housing itself to check the door itself, or slip a camera into the housing and use it to look at the door and the cores.
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Thursday, May 20th, 2021 AT 11:54 AM
Tiny
BATSIBF
  • MEMBER
I can hear it stopping on the end of travel. Waiting on my son to get home to move the dash out of the way right now for anything else.
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Thursday, May 20th, 2021 AT 12:19 PM
Tiny
STEVE W.
  • EXPERT
True, but you may only be hearing a section of the door actually moving. If the top quarter is still OK it would act like the entire door was working, but it actually isn't. If you can get in there and look you may find the answer. It's also possible that something got in there and blocked the air. I repaired one once that a swarm of insects had blocked. That was a mess.
Let us know what you find.
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Thursday, May 20th, 2021 AT 12:54 PM
Tiny
BATSIBF
  • MEMBER
Okay, this is what I m seeing:
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Thursday, May 20th, 2021 AT 1:18 PM
Tiny
STEVE W.
  • EXPERT
Well, that looks like the entire door. Air should be moving across the core with that. Verify that it's fully closed but it looks like it is. To do that you rotate the temp to full cold, then move the door lever so it's at full cold. Once set that is all that controls hot and cold on them. I don't recall if you can run the blower with it apart, but you might want to run a set of jumper leads over to the blower motor and double check that the air is going through the cores properly. I don't really see anything wrong in that video but if the core is getting cold the air should get cold as well.
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Thursday, May 20th, 2021 AT 1:39 PM
Tiny
BATSIBF
  • MEMBER
When I had it running air was blowing hard, I m thinking at this point I might put it back together and find a shop. Everything I m find it should be blowing cold air, it could be the Black Death has filled the coils too?
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Thursday, May 20th, 2021 AT 1:42 PM
Tiny
STEVE W.
  • EXPERT
Possible but the system normally wouldn't get the lines cold if that was the case as it tends to restrict flow and you wouldn't get the signs you have with the condensation and cold on both lines. One of the trades with used vehicles is you don't know the full real service history of them. Did they say anything about replacing a compressor or drier?
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Thursday, May 20th, 2021 AT 4:53 PM
Tiny
BATSIBF
  • MEMBER
Nope, they said the A/C worked great.
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Thursday, May 20th, 2021 AT 5:12 PM
Tiny
BATSIBF
  • MEMBER
I put another question up, about a problem when we put the dash back in still can t find a reason for the blower not working, and the window switches causing the high beam light, ABS light, and another light and ideas about that?
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Thursday, May 20th, 2021 AT 5:14 PM
Tiny
STEVE W.
  • EXPERT
Hmm, sounds like a bad ground connection. Possibly ground 202 on the left side of the instrument panel. It is shared by the dash and the window switches. The blower has a ground on the right side of the dash. I would check those first. Chrysler has a thing for bad grounds, the terminals tend to fail at the crimp. They are all black wires that ground those items.
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Thursday, May 20th, 2021 AT 9:47 PM
Tiny
BATSIBF
  • MEMBER
Okay, I remember seeing them. And that makes sense. I had extra help putting it back together.
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Friday, May 21st, 2021 AT 4:42 AM
Tiny
STEVE W.
  • EXPERT
The earlier Jeeps had something like 6 main grounds on each side of the dash, when they started to fail things would go crazy on them.
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Friday, May 21st, 2021 AT 7:59 AM
Tiny
BATSIBF
  • MEMBER
I bet, this has been driving me nuts.
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Friday, May 21st, 2021 AT 11:30 AM
Tiny
BATSIBF
  • MEMBER
Well the truck is running again, bad grounds and a couple of loose wires. Still no A/C.
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Friday, May 21st, 2021 AT 6:28 PM
Tiny
STEVE W.
  • EXPERT
So you are back to the starting point. At least you know what it isn't, and by repairing the grounds you likely are preventing other failures. You could throw a set of gauges on it and see what the pressures are but your earlier description sounds like it is working somewhat. Just odd that the lines are cold and causing condensation but the air over the core isn't getting cold. About the only thing I can think of would be to recover the charge in it and recharge by weight and test it and see if the compressor is weak or possibly there is a blockage in the system.
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Friday, May 21st, 2021 AT 10:48 PM

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