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sprinkles08, ASE Certified Technician
Category: Car
Satisfied Customers: 22989
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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murano: 2006 Nissan Murano.Have no heat in hvac system. Engine

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2006 Nissan Murano.
Have no heat in hvac system. Engine up to temp, but only cold air coming thru vents.
Cooling system service and flush last year, recovery tank and rad are up to appropriate levels.
Regardless of whether or not hvac system is in auto or manual mode, no heat. when dials are turned to adjust temp to increase, they momentarily display red as if they were going to increase the heat and then the display reverts back to blue with out giving any heat.
Thanks foir your help,
Hello and welcome to JustAnswer!

I see your question has been up for an extended time without a response. Do you still need help?

Customer: replied 4 years ago.


Do you have a single or dual zone system? If it's dual, do the left and right sides blow the same temperature?

Do you get any heat whatsoever or is it always blowing the temperature of the outside air?

Customer: replied 4 years ago.

dual zone, and blows same temp as outside air

Do both sides blow the same temperature?

Customer: replied 4 years ago.

yes same temp both sides

Let's try a battery disconnect to clear fault codes and see if that makes a difference. With the key off disconnect the battery for a minute or so, reconnect it and then see if you have heat or it's still the same.

Customer: replied 4 years ago.

ok, I am going to have to try that tomorrow. We left the Murano at my girlfriends place and used my truck. couldnt keep the windshield clear of condensation.


Not a problem. Let me know how it goes and we'll go from there!

Customer: replied 4 years ago.

Thank you for the "lead". Just so you know, I have no "trouble codes" indicated, but I understand the battery disconnect to try and "reboot" the system.

I will see what time my girl lets us leave and go back to her place.

Thank you again,


You're welcome!

Customer: replied 4 years ago.

Good morning,

Do you know if the self diagnosis functions for the hvac system on the Murano display the codes in the hvac display or do i need a scanner tool?

There is a self test that can be done but it's rather complicated. Did you have any luck with the battery disconnect?

Customer: replied 4 years ago.

lol, not yet, still at my place. just been doin some research and found a service manual download, so i did some reading


Did you find the self test instructions? I'm not sure it will show us anything since the problem is happening on both sides of your dual zone system, but it wouldn't hurt to see if it does find anything.

Customer: replied 4 years ago.

That info is there, and I will resort to that after I do the basics


Let me know what you find and we'll go from there!

Customer: replied 4 years ago.

ok, have disconnected battery and re connected. no change. tried to start the self diagnosis mode, but do not see where the "codes" indicating proper function are supposed to display.

They should come up right on the digital display of the control head.

Customer: replied 4 years ago.

ok, all i got was code 22 and 25, so that is in vehicle temp sensor and sun load. no communication with mixer doors etc

Either of those sensors will cause a problem in automatic mode but not in manual mode. You don't have any heat in manual mode either do you?

I'm assuming that you lost heat on both sides at the same time, you didn't lose one side for a while and then the other?

This didn't start after any work was done in the dash?

Customer: replied 4 years ago.

lost all heat both sides, no heat in manual mode, and no in dash work was done. Asymptomatic until this past wednesday

Have you felt the heater hoses at the firewall to make sure they're both hot when the engine is at operating temperature?

Customer: replied 4 years ago.

re checked, both are even temperature


If they're both hot then you should have at least enough flow through the heater core to at least begin to heat the air. You're blowing outside temperature air so I don't think any air is making it past the heater core.

If it were a single zone system I would be inclined to say you had a blend door or blend door actuator issue, losing heat on both sides of a dual zone system at the same time makes that pretty unlikely. To lose heat on both sides at the same time it would have had to break both blend doors or both actuators would have to fail at the same time.

I believe the problem is going to be the control head itself, especially since you are seeing it turn back to blue when turning the temperature to hot. It sounds like the control head has failed and it's not commanding either of the blend door actuators to move.
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