Low beams not working intermittently

Tiny
302BRONCO435
  • MEMBER
  • 2010 CHEVROLET 1500
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 127,548 MILES
On my way home I noticed that people kept pulling over in front of me. I noticed my low beams coming off and then on as it got darker. The low beams turn off and on without warning. But the high beams work fine and have no issues. So I have found that the low beams will work with the engine off, and the ignition on or off. But as soon as you start the engine the low beams will flicker on and off or just stay off.
Friday, February 26th, 2021 AT 1:41 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,401 POSTS
This sounds like the low beam relay could be bad or headlight switch. To be sure lets do a CAN scan which is the future of automotive repair. you can get a CAN scanner from Amazon for about $50.00. here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

This is because the headlight are controlled by the BCM, but the relay is an easier and much chear fix. here are the headlight wiring diagrams so you can see how the system works with the relay location as well:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

I also included the BCM replacement instruction as well. Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.
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Sunday, February 28th, 2021 AT 7:23 PM

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