Low beam Headlights

Tiny
DHOFF52
  • MEMBER
  • 2000 CHEVROLET IMPALA
  • AUTOMATIC
  • 192,345 MILES
I have checked all fuses and relays, all are fine. When I pull headlight switch the lights will not come on. But MFS will put on brights, daytime running lights work. All blinkers etc work. I checked for power at headlight connector. No 12 volts. Both headlights are out. But I can apply 12 volt to bulb and they work? Wipers act funny, and security light acts funny. Is this the BCM? What can I do? I am stuck.
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Friday, August 19th, 2016 AT 8:01 AM

15 Replies

Tiny
HMAC300
  • EXPERT
Clean battery terminals and have multi function switch checked, it may be bad not allowing low beams to work assuming fuses and relays for head lights have been checked under hood. Then reset security system after cleaning battery. Good idea to get battery checked for condition including load test as well.
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Friday, August 19th, 2016 AT 9:40 AM
Tiny
DHOFF52
  • MEMBER
Okay, I can load test it myself. So the MFS can stop the regular lights from coming on? I do know there is no click on the MFS. I have to hold back for high beams to stay on.

Thanks I will clean battery terminals. And load test it. Dave H
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Friday, August 19th, 2016 AT 10:51 AM
Tiny
HMAC300
  • EXPERT
Yes, multi function switches can make lights not work on low beam. It may be the relay or body module as well not supplying power to dimmer switch try to see if light/blue wire is getting power if it is and none coming out dark/blue then it is the switch. If it does not get power then have it scanned to rule out body module.
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Friday, August 19th, 2016 AT 12:03 PM
Tiny
DHOFF52
  • MEMBER
Okay, thanks so much. I will try all. Great to hear new information.
Dave
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Friday, August 19th, 2016 AT 12:12 PM
Tiny
DHOFF52
  • MEMBER
One question, check the voltage at the MFS or BCM? I believe you meant MFS.
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Friday, August 19th, 2016 AT 12:26 PM
Tiny
HMAC300
  • EXPERT
MFS.
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Friday, August 19th, 2016 AT 12:50 PM
Tiny
DHOFF52
  • MEMBER
Thanks.
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Friday, August 19th, 2016 AT 1:22 PM
Tiny
DHOFF52
  • MEMBER
Ok I've done lots of testing. Coming from harness to lights, there is power on every color wire except the light blue and black. There are 2 dk/ blue 1 pink 1yellow, 1orange 1light blue and black. So what does this mean?
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Saturday, August 27th, 2016 AT 6:49 AM
Tiny
HMAC300
  • EXPERT
If ther eis no power from the lt blu wire in pic that operates the headlamp relay that goes to body module so you would have no low beam the pink wires are for high beam so the bcm may not be getting power. You can try disconnection multi function switch and putting power to that wire in harness and see if lights come on if they do the switch has lost contact if not the body module is bad and should be scanned by a mechanic to verify.
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Saturday, August 27th, 2016 AT 7:04 AM
Tiny
DHOFF52
  • MEMBER
Ok thanks so much. I'm about to figure this out. Get back to you later. Thanks
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Saturday, August 27th, 2016 AT 7:10 AM
Tiny
RENEE
  • ADMIN
Please let us know so it will help others
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Tuesday, August 30th, 2016 AT 9:14 AM
Tiny
DHOFF52
  • MEMBER
I'm am going to finish all my testing once I'm off work for the week. I work 12 hour shifts. I'm going to check for voltage at the MFS switch and apply 12 volts to lt/ blue wire to see if headlights come on. If so I will replace MFS. And I will let everyone know what the issue was. I believe it will be MFS but we will know for sure this week.
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Tuesday, August 30th, 2016 AT 9:40 AM
Tiny
DHOFF52
  • MEMBER
Ok everyone. I got to work on car today. PROBLEM FIXED. With the help from 2CarPros and having some knowledge and the right tools. My Low beams now Work. IT WAS MFS. Multifunction Switch. Thank God it wasn't the BCM. The closest dealership wanted $160. To program new one in the car and $220. Outside of car. 2CarPros has done real knowledgable people on there staff. I would recommend them any time. Once he pointed me in the right direction I used 2 tools to diagnose and fix. I used the Power Probe to activate power and the Load Pro to verify open. 2CarPros was right. Thanks so much now I can move forward to other things now. Yeeehaaaw
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Thursday, September 1st, 2016 AT 9:56 AM
Tiny
DHOFF52
  • MEMBER
If any other people are having these issues 2CarPros is the best
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Thursday, September 1st, 2016 AT 9:58 AM
Tiny
RENEE
  • ADMIN
We are glad you like our service, please tell a friend we are here to help.
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Thursday, September 1st, 2016 AT 10:12 AM

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