C5 Tech Corvette Tech/Performance: LS1 Corvette Technical Info, Internal Engine, External Engine, Tech Topics, Basic Tech, Maintenance, How to Remove & Replace
Sponsored by:
Sponsored by:

Lost My Low Beams

Thread Tools
 
Search this Thread
 
Old May 9, 2009 | 10:18 PM
  #1  
donatcfa's Avatar
donatcfa
Thread Starter
4th Gear
 
Joined: Aug 2008
Posts: 4
Likes: 0
From: San Antonio TX
Default Lost My Low Beams

While driving at night, my low beams suddenly went out while switching between high and low beams. I have inspected all fuses related to the lights in the passenger footwell and the engine compartment, in particular both the L and R low beam fuses in the engine compartment fuse box. No luck. Also, when using remote to unlock, the fog and back-up lights no longer come on momentarily. Amber running lights only illuminate when the lights are in the off position. Running lights lights go off if parking lights are engaged or lights are turned on. Headlight motors work and high beams work. Any ideas? Thanks.
Reply
Old May 9, 2009 | 11:37 PM
  #2  
byronhunter's Avatar
byronhunter
Melting Slicks
15 Year Member
All Eyes On Me
 
Joined: Oct 2007
Posts: 2,383
Likes: 13
From: Kinston North Carolina
Default

Check Voltage on Fuses #8 and #10 in the underhood fuse block. If 0 Volts, probably going to find a problem with multifunction switch. These 2 schematics should help troubleshoot the problem.




Reply
Old May 12, 2009 | 06:34 AM
  #3  
donatcfa's Avatar
donatcfa
Thread Starter
4th Gear
 
Joined: Aug 2008
Posts: 4
Likes: 0
From: San Antonio TX
Default

Dealer says it is the BCM (Body Control Module). $1369.xx. FYI.
Reply
Old May 12, 2009 | 08:06 AM
  #4  
ColeTrain'sC5's Avatar
ColeTrain'sC5
Melting Slicks
10 Year Member
 
Joined: Jun 2007
Posts: 2,172
Likes: 1
From: Sartell Minnesota
Default

i think there is somebody here that rebuilds them but not 100% sure. i would check the things the first guy said before you drop $1400 at the dealer.
Reply
Old May 12, 2009 | 12:21 PM
  #5  
byronhunter's Avatar
byronhunter
Melting Slicks
15 Year Member
All Eyes On Me
 
Joined: Oct 2007
Posts: 2,383
Likes: 13
From: Kinston North Carolina
Default

donatcfa, has the dealer done the proper troubleshooting? If you let them replace the BCM, make sure you don't have to pay that if it dosn't cure the problem!
Reply
Old May 12, 2009 | 12:23 PM
  #6  
byronhunter's Avatar
byronhunter
Melting Slicks
15 Year Member
All Eyes On Me
 
Joined: Oct 2007
Posts: 2,383
Likes: 13
From: Kinston North Carolina
Default

jrprich, that link dosn't work, and besides, it's for the Electronic Brake Control Module.
Reply
Old May 12, 2009 | 12:29 PM
  #7  
lucky131969's Avatar
lucky131969
Tech Contributor
15 Year Member
Active Streak: 30 Days
Community Builder
Liked
 
Joined: Jan 2007
Posts: 19,401
Likes: 1,144
From: Dyer, IN
Default

Originally Posted by donatcfa
Dealer says it is the BCM (Body Control Module). $1369.xx. FYI.
Really? For the low beams not working? Think about the sequence of events here...the only thing you did while driving is turn on the high beams, then the low beams were dead after. So the only thing you touched was the multifunction switch.

Take the wiring diagram to your dealer, and ask them why the tan wire from the multifunction switch runs directly to the low beams and not throught the BCM.

Provided you've checked all fuses, it's probably the mutlifunction switch, but you should verify voltage and ground with a DMM to be sure.
Reply
Old May 12, 2009 | 12:30 PM
  #8  
lucky131969's Avatar
lucky131969
Tech Contributor
15 Year Member
Active Streak: 30 Days
Community Builder
Liked
 
Joined: Jan 2007
Posts: 19,401
Likes: 1,144
From: Dyer, IN
Default

Originally Posted by byronhunter
jrprich, that link dosn't work, and besides, it's for the Electronic Brake Control Module.
You mean the EBCM and BCM are not the same..?.......
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-1

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-2

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-3

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-4

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-5

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-6

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-7

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-8

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-9

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
Old May 12, 2009 | 12:31 PM
  #9  
C4B4the04's Avatar
C4B4the04
Pro
15 Year Member
 
Joined: Jan 2006
Posts: 643
Likes: 2
From: Alexandria Northern Virginia
Default

I'd bet money you could swap the relay on the BCM (and I'd bet thats what is bad if its the BCM at all) just like you can on the door control modules. Man I would go down a road pretty far self-diagnosing before I'd throw a G at headlights.

Those schematics tell you everything you need to know about the circuit. Get some help from somebody good with a voltmeter if it looks like Latin to you and go from there. Sorry you have a problem with it man, sure hope there's a cheap fix.

Cassidy
Reply
Old May 12, 2009 | 12:40 PM
  #10  
lucky131969's Avatar
lucky131969
Tech Contributor
15 Year Member
Active Streak: 30 Days
Community Builder
Liked
 
Joined: Jan 2007
Posts: 19,401
Likes: 1,144
From: Dyer, IN
Default

Originally Posted by C4B4the04
I'd bet money you could swap the relay on the BCM (and I'd bet thats what is bad if its the BCM at all) just like you can on the door control modules.
Ok. Which relay on the BCM would you swap to effect the low beams?
Reply
Old May 12, 2009 | 12:45 PM
  #11  
byronhunter's Avatar
byronhunter
Melting Slicks
15 Year Member
All Eyes On Me
 
Joined: Oct 2007
Posts: 2,383
Likes: 13
From: Kinston North Carolina
Default

Originally Posted by lucky131969
Really? For the low beams not working? Think about the sequence of events here...the only thing you did while driving is turn on the high beams, then the low beams were dead after. So the only thing you touched was the multifunction switch.

Take the wiring diagram to your dealer, and ask them why the tan wire from the multifunction switch runs directly to the low beams and not throught the BCM.

Provided you've checked all fuses, it's probably the mutlifunction switch, but you should verify voltage and ground with a DMM to be sure.
Thanks Lucky, I was waiting for you to come in, it's crazy aint it???
Reply
Old May 12, 2009 | 12:47 PM
  #12  
byronhunter's Avatar
byronhunter
Melting Slicks
15 Year Member
All Eyes On Me
 
Joined: Oct 2007
Posts: 2,383
Likes: 13
From: Kinston North Carolina
Default

Originally Posted by lucky131969
Ok. Which relay on the BCM would you swap to effect the low beams?
Reply
Old May 13, 2009 | 01:14 AM
  #13  
toddk's Avatar
toddk
Racer
15 Year Member
 
Joined: Feb 2004
Posts: 359
Likes: 7
From: St. Paul MN
Default

Originally Posted by lucky131969
Take the wiring diagram to your dealer, and ask them why the tan wire from the multifunction switch runs directly to the low beams and not throught the BCM.

Provided you've checked all fuses, it's probably the mutlifunction switch, but you should verify voltage and ground with a DMM to be sure.
It looks to me like the Tan wire is direct to the low beams, except its always-hot source is switched by relay 44 (automatic lamp control relay) which is controlled by the BCM. The GM SI says this is used by the twilight sentinel option.

Have you tried turning off Twilight Sentinel in the DIC options? I'd also check for a stuck relay 44 by verifying if the BCM is really providing ground on terminal H3 with a multimeter.

Todd
Reply
Old May 13, 2009 | 11:26 AM
  #14  
lucky131969's Avatar
lucky131969
Tech Contributor
15 Year Member
Active Streak: 30 Days
Community Builder
Liked
 
Joined: Jan 2007
Posts: 19,401
Likes: 1,144
From: Dyer, IN
Default

Originally Posted by toddk
It looks to me like the Tan wire is direct to the low beams, except its always-hot source is switched by relay 44 (automatic lamp control relay) which is controlled by the BCM. The GM SI says this is used by the twilight sentinel option.
So by your interpretation of the schematic, you cannot manually turn on the headlights if relay 44 goes bad.
Reply
Old May 13, 2009 | 02:58 PM
  #15  
toddk's Avatar
toddk
Racer
15 Year Member
 
Joined: Feb 2004
Posts: 359
Likes: 7
From: St. Paul MN
Default

Originally Posted by lucky131969
So by your interpretation of the schematic, you cannot manually turn on the headlights if relay 44 goes bad.
There are a many "what if" scenarios. After re-reviewing the schematic, I would rule out relay 44. It looks like there are two routes to get unswitched power. First is if relay 44 is grounded by the BCM, all the "default paths" through the headlamp switch will complete the circuit. Second is through the E4-W wire, also relying on the headlamp switch being on in low-beam mode.

The reading the OP's original comment that the headlight doors do open and close properly also tells me that relay 44 is probably OK. This points back to bad contacts in the headlamp switch itself.

Todd
Reply
Old May 13, 2009 | 03:42 PM
  #16  
Bill Curlee's Avatar
Bill Curlee
Tech Contributor
Supporting Lifetime Gold
Veteran: Navy
25 Year Member
Liked
Community Favorite
 
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Default

This post is fun Give us your $1400. We can have fun with it!

You pronounced it wrong! ITs,,, STEALERSHIP!.

If I were you I would go back there have a word with who ever told you that the BCM was bad. I would be PISSED!

Thats some POOR Stealership troubleshooting but its VERY profitable!

BC
Reply
Old May 13, 2009 | 05:15 PM
  #17  
ColeTrain'sC5's Avatar
ColeTrain'sC5
Melting Slicks
10 Year Member
 
Joined: Jun 2007
Posts: 2,172
Likes: 1
From: Sartell Minnesota
Default

The Bill has spoken lol i'd listen to him he knows his ****
Reply

Get notified of new replies

To Lost My Low Beams

Old May 13, 2009 | 05:33 PM
  #18  
byronhunter's Avatar
byronhunter
Melting Slicks
15 Year Member
All Eyes On Me
 
Joined: Oct 2007
Posts: 2,383
Likes: 13
From: Kinston North Carolina
Default

Originally Posted by toddk
There are a many "what if" scenarios.

This points back to bad contacts in the headlamp switch itself.

Todd
That's what I said 4 days ago!!!!!
the only "what if" scenario I see is, what if the OP pays the dealership $1300 to fix it.
Reply
Old May 13, 2009 | 05:36 PM
  #19  
lucky131969's Avatar
lucky131969
Tech Contributor
15 Year Member
Active Streak: 30 Days
Community Builder
Liked
 
Joined: Jan 2007
Posts: 19,401
Likes: 1,144
From: Dyer, IN
Default

Originally Posted by byronhunter
That's what I said 4 days ago!!!!!
the only "what if" scenario I see is, what if the OP pays the dealership $1300 to fix it.
Hey, settle down byronhunter....as ColeTrain'sC5 has stated.......Bill has spoken....
Reply
Old May 13, 2009 | 05:57 PM
  #20  
byronhunter's Avatar
byronhunter
Melting Slicks
15 Year Member
All Eyes On Me
 
Joined: Oct 2007
Posts: 2,383
Likes: 13
From: Kinston North Carolina
Default

OK Lucky, I'm
Reply



All times are GMT -4. The time now is 02:52 AM.

story-0
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-1
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-2
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-3
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-4
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-5
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-6
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-7
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-8
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-9
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE