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Q: Temp gauge goes up a quarter when headlights are turned on in both idle or driving

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Both upper and lower hoses are hot and firm. No visible coolant leaks or coolant reservoir loss. I have cleaned the grounds for the headlights, flushed the radiator and also added an additional ground wire to the transmission but no difference. When the radiator fan starts the temp gauge goes back to its normal halfway position and it climbs up again after some time.

My car has 232994 miles.
My car has an automatic transmission.

A: Hi there. If the engine is running at the c...

Hi there. If the engine is running at the correct temperature at all other times, except when you turn on the headlamps then you do not have a cooling system issue. Most of the time, this is a short in the instrument cluster. This is common on this vehicle. It can also be an issue with the wiring coming from the coolant temperature sensor, but that it not as likely. I typically check the wiring from the sensor to make sure that it is not shorting against any other wiring. If that is fine then I typically will replace the instrument cluster. If you are going to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to inspect the electrical circuits in your car.

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