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Pete
Pete, Auto Service Technician
Category: Chevy
Satisfied Customers: 24725
Experience:  14 years GM dealer Technician.
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I have a 2004 blazer 4x4. My issue is I only get cold or

Customer Question

I have a 2004 blazer 4x4.
My issue is I only get cold or mixed air from the vents. I replaced the mix door control motor assembly (old was good) and checked for broken doors. If I push in slightly on the distribution selector on the console, I gradually get some heat. Could I have a vacuum issue even though the mix door operates? How would outside air get past the mix door? It seems to be swung all the way. Is there another entry point or door? Also I recently got codes 0101 & 0155. 0101 cleared. 0155 came back within 5 min. I know I have a periodic slight air leak on top of the carb intake.
Submitted: 11 months ago.
Category: Chevy
Expert:  Pete replied 11 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.

What can fail and cause this issue here is the control switch itself on the dash heater controller.It is a vacuum actuated switch as seen in the picture below with the vacuum manifold attachment.

https://www.dropbox.com/s/knjy1b7br0zv30p/vac-01-04.gif?dl=0

The other issue is this vacuum manifold attachment warps needing replaced as it allows air to leak past it causing this here.In some cases you may see transmission fluid in this attachment and this is due to the switch on top of the transfer case leaking needing replaced then the vacuum manifold replaced at the control head on the dash and the control head mode switch replaced as well.

These are the main causes for your heater/ac system here that needs checked into further and repaired from there.

Code P0155 indicates a fault with oxygen sensor bank 2 sensor 1.This is the sensor located on the passenger side of the engine in the exhaust manifold or pipe that connects to the exhaust manifold.The oxygen sensor itself failing is most common needing replaced to correct this code issue here.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.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 11 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 11 months ago.
Expert:  Pete replied 11 months ago.

I will send the additional service requested.

Thanks Pete

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