Q: My oil pressure gauge read high with lights on

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My oil pressure gauge reads a little over 40 normally but when I turn my headlights on, the gauge reads over 90 and I don't know why..can you give me some advice on how to fix this problem?

My car has 280000 miles.
My car has an automatic transmission.

The oil pressure gauge uses a resistance sensor to supply the oil pressure reading from the engine’s actual oil pressure. The oil pressure sensor on these engines may leak and get oil in the connector and cause erratic readings on the gauge.

I would first replace the oil pressure sensor and clean the connector. Then see if the problem still happens. The head lights may somehow be feeding back into the instrument cluster. This would need extensive testing if that is the case by removing the cluster and checking all the grounds and connections of the connectors on the back of the cluster.

Also, all the headlight grounds will need to be checked. There are two grounds to look at. One on the back of the cluster and the other on the instrument panel frame behind the instrument cluster. Check both these grounds to see if one is loose or broken.

If you need some assistance with these checks, get some help from a certified technician, such as one from YourMechanic. One of our mobile technicians will be able to come to your home or office to diagnose this electrical issue and help you fix it accordingly. Best of luck.

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