A/C blows cold then hot

Tiny
NEWTC84
  • MEMBER
  • 1935 FORD F-350
Hello, I have a 2000 F350 diesel 2wd with 133000 miles. The A/C blows cold for about 10 minutes after I start running it, then it goes hot. I already replaced the cycling switch, and topped off the freon. After I turn the ac off for a while then turn it back on and it blows cold again for a while then hot.

Okay, I drove the truck until the A/C started acting up. I observed the compressor clutch activity. The clutch would kick on and off until it started to blow hot air. When I opened the hood I found that the compressor clutch was stuck (not moving, I'm not sure if that means it was on or off). I connected the gauges and the low side pressure was sky high! I jumped the wires like you said at the connector and the clutch kicked back off (or on) and the gauge pressure dropped into the normal zone. So, what should I do next? I just replaced that switch, so is something else bad?

That is actually the second time I have replaced that switch. Both times it did nothing. Is there no other way that it could be something else? I will try to call ford and buy from them. The previous 2 parts I bought from auto parts stores like Napa and Carquest.

I think I may have done something a little stupid. The connector has 4 plug ports, while there are only 2 plugs from the switch. Only 2 of the ports on the plug connector have metal contact in them. I think I plugged it in so that the plugs were not contacting the ports correctly. I know. Laugh at me if you wish. I will try to plug it in correctly and let you know the outcome. Ha Ha! I hope we have all made these simple mistakes.

I bought another switch, which was my third one in about 2 months. This time from Ford dealer. I got the same problem, hot air after a while. I jumpered the wires again and the compressor kicked on just like before. Is there something else it could be? You said there is one other thing you could think of.

the gap was at.02 inches, but the front of the radiator and the rear of the condenser are both cover with junk. I will clean this off with your tool. Hope it works. I will let you know.

I replaced the cycle switch 3 times, so I know that is working, and I made the tool you described and blew out a bunch of sand and junk from both the radiator and the condenser (and the other coolers that are there). My test drive revealed the same old problem. I agree with the diagnosis about the compressor clutch not engaging because of heat, because the clutch stops working a lot sooner when the outside temp is hotter, or when I am doing more stop and go driving. So, is there anything else I can do? Or do you think I need to start replacing things?

I tapped the clutch face with a hammer ever so slightly when it was stuck, and on it came! So, I am curious. Is there something I can replace to help the clutch from sticking, or do I need a whole new compressor?

Sounds like it is not cycling? Any ideas?
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Tuesday, July 24th, 2007 AT 10:43 PM

15 Replies

Tiny
KEN
  • ADMIN
Hello,

What happens is the clutch coil becomes weak and does not pull the clutch into the hub. This is a common problem with compressors. At this point it is best to get a new compressor from Amazon and replace it.

https://www.amazon.com/gp/product/B00JXYHAD4/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&tag=2carprcom-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B00JXYHAD4&linkId=f60bd9853810fe87c12488b157fa227b

180 bucks is great for a new compressor. Here is a guide to show you what you are in for when replacing the unit.

https://www.2carpros.com/articles/replace-air-conditioner-compressor

and

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

Make sure you check for leaks when done

https://www.2carpros.com/articles/air-conditioner-leak-detection

Please let us know what happens.

Cheers, Ken

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Monday, June 12th, 2017 AT 3:08 PM
Tiny
NEWTC84
  • MEMBER
  • 1935 FORD F-350
Hello, I have a 2000 Ford F350 Diesel 7.3 L truck, 2wd with 130 K miles. The A/C system is acting a little strange lately. First of all, the a/c fan only comes on sometimes. I can hear the compressor and components turning on under the hood, but the air only blows out sometimes. If it does not work, I turn off the truck, and wait a while, then start it again, it might work. Also, when the fan is working, the a/c starts out cold, and after a while it blows hot, then cold, then hot and pretty soon it just blows hot. It seems to stay cold longer when it is cool outside. When it is hot, it tends to get warm much sooner. I already had freon added and the system charged, and a switch changed out. Any ideas?
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Monday, June 12th, 2017 AT 3:09 PM (Merged)
Tiny
NEWTC84
  • MEMBER
I do not have auto temp control. The switch that was replaced on the a/c. I am not sure what switch was replaced, sorry, iI don't mind replacing it again. Any suggestions?
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Monday, June 12th, 2017 AT 3:09 PM (Merged)
Tiny
NEWTC84
  • MEMBER
Could you tell me where to locate the blower motor, and anything special I need to do in order to replace it, or simply take it out and install the new one? Thanks.
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Monday, June 12th, 2017 AT 3:09 PM (Merged)
Tiny
TNEUB
  • MEMBER
Testing the system, while HOT, a test light showed power to the clutch but it was not engaging the compressor. I found the clutch coil would release when hot and would reengage when it cooled enough.
To resolve the issue I replaced the entire compressorclutchcoil, accumulator, orifice tube and condenser. Pulled a vacuum on the system, recharged with R134. Blowing 37F again nice!
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Monday, June 12th, 2017 AT 3:09 PM (Merged)
Tiny
TNEUB
  • MEMBER
  • 2001 FORD F-350
  • 7.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
Air conditioner blows cold then hot.
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Monday, June 12th, 2017 AT 3:09 PM (Merged)
Tiny
HMAC300
  • EXPERT
Check for a vacuum leak going to one of the actuators then have air conditioner checked for freezing up.
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Monday, June 12th, 2017 AT 3:09 PM (Merged)
Tiny
TNEUB
  • MEMBER
Testing the system, while HOT, a test light showed power to the clutch but it was not engaging the compressor. I found the clutch coil would release when hot and would reengage when it cooled enough.
To resolve the issue I replaced the entire compressor clutch coil, accumulator, orifice tube and condenser. Pulled a vacuum on the system, recharged with R134. Blowing 37F again nice!
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Monday, June 12th, 2017 AT 3:09 PM (Merged)
Tiny
KEN
  • ADMIN
Great to hear, please use 2Carpros anytime we are here to help.

Best, Ken
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Monday, June 12th, 2017 AT 3:09 PM (Merged)
Tiny
JERRY PLUMB
  • MEMBER
  • 1999 FORD F-350
Air Conditioning problem
1999 Ford F350 Two Wheel Drive 281125 miles

airconditioning blows cool then hot after opperation temp. Is reached, I have changed the orifice filter?
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Monday, June 12th, 2017 AT 3:10 PM (Merged)
Tiny
MERLIN2021
  • EXPERT
Do you have the high and low side gauge readings? It sounds like the system may have a blockage, Tell me what the outside temp and humidity is, and count the seconds between compressor cycling on and off. Also tell me if you have auto temp, or manual A/C.
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Monday, June 12th, 2017 AT 3:10 PM (Merged)
Tiny
MUZQUIZ12
  • MEMBER
  • 1995 FORD F-350
  • 200,000 MILES
My ac works I dont. Think it blows enough its still hot in truck I got. Tint I put more freon wat do I do my kids sweat in the truck as I is there a more powerful ac fan I can purchase???????????????
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Monday, June 12th, 2017 AT 3:10 PM (Merged)
Tiny
HMAC300
  • EXPERT
Have a pro run a performance test on the a/c system. You may have put to much in. It could be an actuator under dash as well.
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Monday, June 12th, 2017 AT 3:10 PM (Merged)
Tiny
IED3W
  • MEMBER
  • 2000 FORD F-350
  • V8
  • 2WD
  • AUTOMATIC
  • 250,000 MILES
Air Conditioning problem
2000 Ford F350 V8 Two Wheel Drive Automatic 250000 miles

A/C works well at first but after 10-15 minutes it turns hot for 10-15 minutes then turns cold again. If I race the engine it will start blowing cold again for a few minutes
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Monday, June 12th, 2017 AT 3:10 PM (Merged)
Tiny
OBXAUTOMEDIC
  • EXPERT
Few things to check - Sarter truck turn a/c on watch a/c clutch, does it stay on for a couple minutes then cut off or does it kick in and out frequently? If it cuts in and out frequently it is most likely low on freon. If it is fully charged check the A/C Compressure Clutch Cycling Pressure Switch. It looks like this....


http://www.2carpros.com/forum/automotive_pictures/188069_accyclingswutch_1.jpg

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Monday, June 12th, 2017 AT 3:10 PM (Merged)

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