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Rick
Rick, Nissan Master Technician
Category: Nissan
Satisfied Customers: 503
Experience:  27 Years working in Nissan Dealerships Currently working for Nissan Dealer
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99 Maxima: blowing hot air..They can bypass the compressor..temp gauge

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99 Maxima-A/C blowing hot air. They can bypass the compressor to make it work, but obviously that's not an option. The temp gauge on the dash seems accurate. They replaced the internal air sensor that tells the a/c what temp to go to, and that didn't help. Now they're thinking maybe they need to "re-set" the system after this new component was changed but are having trouble finding the re-set. I think they don't know what they're doing. What should be done?

Hello I will help with your question please remember to click the ACCEPT when done I don't get paid unless you do

 

I'm assuming that you have automatic temperature control a/c and if they are jumping the compressor to make it come on and the a/c gets cold and seems to work normally then the controls to the compressor is what needs to be addressed I like to start from the compressor and work back to the ECM which provides the ground for the compressor relay , it sounds like there is no power getting to the compressor clutch so I would first remove the a/c relay and check the terminals there two of them-terminals 1 and 5 should have power from two different fuses if they have power then the problem is on the ground side of the relay which comes from the ECM terminal 2 a black/red wire should be giving the ground when the a/c is turned on if thats not happening it may be the ECM is causing the problem or the ECM is not receiving a signal from the a/c amp to turn it on , in that case it gets complicated I have a diagram to give you and the location of the fuses to check that may make it a little clearer

give me a few minutes to post the diagram my computer is having some issues

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graphicgraphicsorry about the delay here are the pictures

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Rick and 3 other Nissan Specialists are ready to help you
Customer: replied 7 years ago.
Hi,
Pursuant to my last question, The temp sensor for the a/c no longer seems to be the issue. I'm now being told the computer is not working. That I either need a new computer or they can create a toggle switch to bypass the computer to turn on when I want a/c.

Are these the only two options when the computer is not working? I don't know why they thought it was the temp sensor in the dash and now the computer. Will I have heat? Or does it just affect the a/c? Thanks!
I'm not a big fan of putting in a bypass with a toggle switch - if the problem is the ECM is not giving the ground signal to the a/c relay then most likely its the controls to the a/c - the ECM could be the problem but as a general rule of thumb if the engine starts and runs normally the ECM is ok , it is more likely that the control head for the heater/ac is not sending a signal to the ECM to turn on the a/c I have replaced more than my fair share of control heads for no a/c and other heater and a/c problems . it could be worth a try to bring by a Nissan dealer to take a look . the issue I have with a bypass is sometimes doing that has a bad affect on other electrical systems