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Dr. Hamman
Dr. Hamman, Engineer, Technician
Category: Nissan
Satisfied Customers: 6286
Experience:  30+ years experience. Turbo, Fuel, electrical, and Ignition Specialist
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my temp gauge go up when I turn on my A/C

This answer was rated:

why does my temp gauge go up when I turn on my A/C and down when I turn my A/C off? How do I fix this problem?

DR Hamman :

 


I would have the reading of the temperature gauges conformed by measuring the actual temperature of the engine, using a non contact IR thermometer, with the AC on and off. Simply because this is a very unusual symptom. I have actually seen this problem a few times. It normally occurs when the extra airflow the fans used to cool the AC condenser coils, actually are effective enough to lower the engine temperature too. Most of the time this indicates problems with the fan that cools the engine. This symptom indicates the fan cooling the engine could be having problems, so this possibility should be explored. If you have any more questions, as always, I am here to help. Good luck with it, have a great day, and Thanks for using Just Answer.

I hope this helps, 100% satisfaction is my goal. Myself personally, and Just Answer are here to serve you. If the answer is not clear, let me know what additional help you need, and I will assist you further. When you're satisfied, and feel you can leave a positive feedback please accept my answer. I don't get paid unless you do. A bonus and positive feedback are always appreciated, good luck and Thanks.



 


 


 

Customer:

What readings am I looking for when I use the IR thermometer? Like what temp should it give me when the A/C is on as oppose to when it's off?

DR Hamman :

 


Different parts of the engine will give different readings. The cylinder head would be a good target area. More than a specific temperature we are wanting to look for a differential, that would coincide with the temperature gauges reading. We are basically wanting to see if the temperature gauge is reacting correctly. Sometimes there can be electrical problems that make gauges readings to become inaccurate. So the different readings will allow us to evaluate the readings of the temperature gauge. If you have any more questions, as always, I am here to help. Good luck with it, have a great day, and Thanks for using Just Answer.

I hope this helps, 100% satisfaction is my goal. Myself personally, and Just Answer are here to serve you. If the answer is not clear, let me know what additional help you need, and I will assist you further. When you're satisfied, and feel you can leave a positive feedback please accept my answer. I don't get paid unless you do. A bonus and positive feedback are always appreciated, good luck and Thanks.



 


 


 

Customer:

I will be purchasing a IR Non-contact thermometer today. I will take the readings and get back to you.

Customer:

Also what electrical problems the car may be experiencing that would cause the gauges readings to become inaccurate?

DR Hamman :

Hi, I am a professional certified mechanic, with an engineering background, and 35+ years experience. I will do my best to assist you. Also keep in mind I don't know if you are a pro or a novice so we may have to fine tune the answer. Feel free to add any additional info you feel is needed as we go on. Always keep in mind that I am here to help you with any questions.


 



Power or ground connection issues. A wire with the plastic rubbed off, or a bad sending unit, can cause problems like this. There is a problem called ground feedback that cause problems like this, it is caused by loose/bad ground connections in a related circuit. The power backflows and can cause gauge readings to fluctuate. It can be a tough problem to solve even for a pro. If you have any more questions, as always, I am here to help. Good luck with it, have a great day, and Thanks for using Just Answer.

I hope this helps, 100% satisfaction is my goal. Myself personally, and Just Answer are here to serve you. If the answer is not clear, let me know what additional help you need, and I will assist you further. A bonus and positive feedback are always appreciated, good luck and Thanks.


 


 


 

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