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Q: Turning brights on causes the engine to die

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I just purchased this used Yukon and I was looking it over in my driveway. I had it idling with the hood up when I noticed the left headlight was really dim. My uncle told me to turn the brights on and when I did the vehicle just died. It dies every time you turn the brights on. Doesn't matter if you push the lever forward or back.

My car has 160000 miles.
My car has an automatic transmission.

A: Hi. This sounds like the the alternator is ...

Hi. This sounds like the the alternator is weak and is going bad. When you turn on the head lights, A/C system, or radio it puts a load on the alternator and the alternator should be able to handle this load if it is working properly. Your alternator seems not to be able to handle the load from putting on the high beams. If you need help with this repair, a certified professional from YourMechanic can come to your home or office to replace the alternator for you.

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