Headlights and taillights only work on auto

Tiny
CHEVY1978
  • MEMBER
  • 2007 CHEVROLET SILVERADO
  • 200,000 MILES
Brights work when on auto. All interior lights work. Lights will not come on in daytime but work fine when gets dark. Also DRL relay is getting very hot. Plan to replace tomorrow.
Friday, August 30th, 2019 AT 6:16 PM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,070 POSTS
Hello,

It sounds like the BCM is going out. To be sure there are 4 relays and a hand full of fuses that run the system lets check those first. here are two guides to help with the headlight wiring diagrams below so you can see how the system works and which fuses and relays to test and their locations as well:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

and

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

Here are the BCM replacement instructions just in case. Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

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Sunday, September 1st, 2019 AT 11:16 AM
Tiny
CHEVY1978
  • MEMBER
  • 2 POSTS
I removed and reinstalled DRL relay and everything started working. I have another one ordered. So far so good thanks for the help.
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Monday, September 2nd, 2019 AT 6:16 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,070 POSTS
Nice work, we are here to help, please use 2CarPros anytime. Let me know if the problem continues.
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Tuesday, September 3rd, 2019 AT 9:27 AM

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