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Kiatech, ASE Certified Technician
Category: Car
Satisfied Customers: 400
Experience:  30+ years experience,ASE certified,KIA certified Master Technician,Ford factory trained
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1999 Infiniti Q45: odometer..Air conditioner works..mechanic says

Resolved Question:

Wife's car is a 1999 Infiniti Q45 with 146,824 miles on the odometer. Air conditioner works intermittently. Local (non-dealer) mechanic says it needs a new compressor. From reading posts on I have come to believe that there may be other solutions that are less costly.

Any suggestions?
Submitted: 7 years ago.
Category: Car
Expert:  Kiatech replied 7 years ago.

Hi JACUSTOMER-nns72eco , Thank you for using JustAnswer.


When the a/c is not cold,is the compressor running?

Customer: replied 7 years ago.
I don't know how to determine if it is or not but the air coming out of the vents is warm not cold.
Expert:  Kiatech replied 7 years ago.

When the engine is running and the air is on.The compressor clutch disk should be turning.(see picture)







Try running the self diagnostic on the system. Here are the step by step instructions.Record any codes.






Edited by Kiatech on 6/1/2010 at 12:47 AM EST
Customer: replied 7 years ago.
It's dark outside now. I will run the tests in the AM and get back to you then.
Expert:  Kiatech replied 7 years ago.
Customer: replied 7 years ago.

Diagnostic complete. In step 1 the display was complete (there was no part of the segment that did not display).

In step 2 the second digit was a 5 that flashed twice. No other codes appeared. In step 3 code 30 appeared in the display.I believe that step 4 produced the proper codes through 48. In step 5 code 51 appeared.then an indication that ambient temp was 81, then 89 for in vehicle sensor,, then 79 for the intake sensor and 52 was displayed when I pressed the REC control and did not blink.


I am not sure that I did everything right but when I repeated the procedure I saw the same result.

Expert:  Kiatech replied 7 years ago.

Do you have access to a set of a/c gages?( Advance Auto Parts will loan tools w/deposit) You need to check the pressures. This car has a variable displacement compressor. The have been known to work intermittently.So it is possible the compressor is bad. Depending on the production date of your car. A used compressor runs anywhere from $75.00 to $250.00 .Try its a used parts locater.It searches salvage yards all over the US.

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