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Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Chevy
Satisfied Customers: 48703
Experience:  16 years of experience
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Been have a/c will blow cold the suddenly stop and go hot.

Customer Question

Been have a/c will blow cold the suddenly stop and go hot. shut off truck and restart will blow cold again.
JA: What is the model/year of your Chevy?
Customer: 2005 Silverado
JA: Are you fixing your Silverado yourself? What have you tried so far?
Customer: yes
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 2 months ago.
Category: Chevy
Expert:  Chris (aka-Moose) replied 2 months ago.

Welcome, I'm Chris (aka Moose).

  • Although I work here everyday, please understand it is not all day and rarely morning time.
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  • Thanks, let's get started.

Is it blowing heat or just blowing outside air temp?

When this occurs if you just open the hood and grab the AC lines at the firewall are they freezing cold?

Customer: replied 2 months ago.
Ok okay total history is it will work then it will shut down when it shuts down the compressor is not turning you shut the truck off restart it and it will blow cold this last time it went 4 days didn't work at all checked it check fuses everything yesterday after I sent the request started the truck up everything worked as supposed to and would run you out cold there's something in the electrical system that is causing this to stop blowing I know a lot of people and lot I've read is the actuator door usually when that happens one side blows cold one side blows hot this blows hot both sides not necessarily sure it's outside air temp or if it is heat simply because I live in Miami not sure where to go next other than I may just have to take it to a shop and have it diagnosed there's got to be something in the electrical system mine is the automatic temperature control and this started a year ago and it just progressively gets a little worse at a time this is the second time then it's gone off and not worked for 3 or 4 days and then turned back on
Expert:  Chris (aka-Moose) replied 2 months ago.

What size truck is this and which engine?

Are you good with wire diagrams and electrical testing?

Customer: replied 2 months ago.
It's the 5/3 and yes I'm good with electrical diagnosis
Expert:  Chris (aka-Moose) replied 2 months ago.

Not sure what 5/3 means

Is this a 1500-2500-3500 and which engine?

Customer: replied 2 months ago.
1500. 5.3
Expert:  Chris (aka-Moose) replied 2 months ago.

Here is your wire diagram

The PCM controls the AC clutch relay. The PCM uses the low and high pressure switches for input and the HVAC controller for AC request. We need to know what the PCM is seeing from those pressure switches to see why it is no longer commanding the AC on. A scan tool is needed to do that. Normally I find a sticking high pressure switch to blame.

Now that I have posted a partial or complete answer, you will see you can rate me. The deposit you have already paid is not transferred to me until you rate me. I would like to receive nothing less than 5 star excellent ratings. So if we are not there yet, please reply and let me help more. If you're not pleased, let me know because rating bad does not result in a refund, there are better options. Rating now will not close this post nor prevent replying. Thanks Chris