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Pete, Auto Service Technician
Category: Chevy
Satisfied Customers: 27813
Experience:  14 years GM dealer Technician.
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This is my issue too: chevy tahoe: Z71..only blows cold air

Resolved Question:

this is my issue too :
chevy tahoe: Z71..only blows cold air
Canadafix was working on,
no trouble codes and computer was changed. was at the shop too. No fix yet. I figured that I would give this a try....
Submitted: 8 months ago.
Category: Chevy
Expert:  Pete replied 8 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

Is this cold air occuring with the temp set on hot?

Let me know so we can continue,thanks Pete.

Customer: replied 8 months ago.
a/c is on all the time regardless of the temp outside. based on the code reader all the inside cabin air is 170 degrees. so naturally the a/c would be on. the temp sensors have all been verified to be functioning properly. no vehicle codes logged. Rear control unit has been isolated from the system.
Expert:  Pete replied 8 months ago.

Was the computer on the front dash for heat/ac operation replaced?

Customer: replied 8 months ago.
not the front computer the rear computer was replaced. the front system operates normally.
is the rear computer a slave to the front computer?
Expert:  Pete replied 8 months ago.

The rear is a slave to the front.If the temp reading inside is 170 all of the time and the temp sensors were replaced already this indicates the front ac/heater control unit needs replaced.If this front control is one that has AUTO settings for AUTO temp controls then it will need programmed by a GM dealer or authorized repair center after it is replaced.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 8 months ago.
I have to take it to the dealer, but I can replace the part myself? will this prevent the heater from working until the computer is programmed?
Expert:  Pete replied 8 months ago.

It does have to be programmed unfortunately to operate.It may not operate at all or properly until it is programmed but you can replace it yourself then have it programmed.Programming usually takes less then 15 minutes to have done.

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete