C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Problem with brake lights

Thread Tools
 
Search this Thread
 
Old Dec 6, 2018 | 11:30 AM
  #1  
Simon Dickens's Avatar
Simon Dickens
Thread Starter
Intermediate
 
Joined: Nov 2018
Posts: 43
Likes: 0
From: ManchesTer
Default Problem with brake lights

hello all
thanks for help getting car running again, justvworking my way through some of the other faults brake lights I'm having problems . It's a Japan import so has orange direction indicators with stop lights in the outer lamps.
i have side lights and indicators but no stop lights or high level brake light working.

i don't have a wiring diagram but this is what I've done so far 👍
I have removed the brake light switch see image




on the main 3 pin switch with orange white and on with ignition on I have 12v on the middle pin orange wire.

if I continuity check the wire to the rear lamp connector plug the grey wire in the picture then goes to green on light side of plug this is for the stop light I have continuity but no voltage ?

also I assume the white wire is for the high level brake light as it has some kind of resistor on it see pic as high level is led type.

i tried bridging the orange power wire with both the blue and white wire one at a time still no brake lights ?

there is another two way connector on the brake light switch blue connector with ignition on it has 12v on one of the wires (sorry forgot which one&#129315
As far as I can tell the brake light switch works I have tested as follows with the switch button pressed in as if brake pedal not pressed. On the blue connector it makes a circuit, on the 3 way connector the contacts are apart 12v on centre pin but no continuity on the white or blue ,
let the switch button out blue connector circuit breaks
3 way connector contacts connect power continuity across the blue and white wire but still no power to the grey wire at the light connector block ?

the orange wire on the 3 way connector and one of the wires in the blue connector showing 12v with ignition on both make continuity to the gray green on the light plug but no power .

What am I missing ?

lastly I put a power probe into the back of the gray green wire and put 12v down the wire back brake lights work?

this one is stumping me

finally what's the easiest way to test the high level led brake light where is the connector plug

thanks in adavane .

ive fixed the LCD dash four new bulbs,
and fixed the windows new toggle switchs

im nearly there 😂🤣😂

any help welcome. I am wondering if anyone has a wiring diagram it's a 1987 c4 ls1 corvette

thanks guys I am thinking is there another relay /switch that sends the power from the brake light switch to the grey wire to green at the light when the brake pedal is pressed.
i should mention as well the brakecwarning light is staying brakes working is this because brake lights are out? Can cruise control brake light switch cause my problem ?

Its giving me a headache 🤕








Reply
Old Dec 6, 2018 | 01:29 PM
  #2  
Simon Dickens's Avatar
Simon Dickens
Thread Starter
Intermediate
 
Joined: Nov 2018
Posts: 43
Likes: 0
From: ManchesTer
Default

Forgot to mention headlamp flash seems to have stopped working whilst I have been trying to solve the brake light issue not sure if this will have any bearing on the fault finding for the brake lights

guess ill I'll have to check that one out next 😂😂😂
another job to add to the list 😁
Reply
Old Dec 6, 2018 | 02:13 PM
  #3  
Kevova's Avatar
Kevova
Le Mans Master
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Default

No wiring diagram is a problem. Do any brake lamps work. Blue wire at stoplight switch is for high level. Is it possible lower red was just a running light, and the inner reds were tail and brake lamps.
Reply
Old Dec 6, 2018 | 04:40 PM
  #4  
Simon Dickens's Avatar
Simon Dickens
Thread Starter
Intermediate
 
Joined: Nov 2018
Posts: 43
Likes: 0
From: ManchesTer
Default

No brake lights work all
Reply
Old Dec 6, 2018 | 04:55 PM
  #5  
Kevova's Avatar
Kevova
Le Mans Master
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Default

Do lights and hazards work? 12v goes from switch through turn signal switch to rear lamps. Blue wire is a separate circuit to high level stop. Blown fuses? Owners manual? You need to invest in manuals preferably factory service manuals.
Reply
Old Dec 7, 2018 | 01:55 AM
  #6  
Simon Dickens's Avatar
Simon Dickens
Thread Starter
Intermediate
 
Joined: Nov 2018
Posts: 43
Likes: 0
From: ManchesTer
Default

  • I have manuals coming but they are coming from a long way the good old usa 😂
  • The hazards where working but I haven't checked them recently
ill check them again fuse fuse that says brake in fuse box is good .

​​​​​​​i lol keep trying 👍
Reply
Old Dec 7, 2018 | 02:53 AM
  #7  
JoBy's Avatar
JoBy
Melting Slicks
25 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2001
Posts: 2,150
Likes: 304
From: Timra, Sweden
Default

It seems like someone did not like to change the light bulbs the correct way.




This is 1984 scematics but it should be similar. The big blue box is the insides of the turn indicator lever.
As you see the indicator lever selects between stop lamp signal and flasher relay. The hazard is also selected here.

To convert to 'export' you cut the white wire from the stop switch. Then you use the blue instead, same as third brake light to the brake light function. Old flash/brake is now only flash.


Reply
Old Dec 7, 2018 | 04:13 AM
  #8  
Simon Dickens's Avatar
Simon Dickens
Thread Starter
Intermediate
 
Joined: Nov 2018
Posts: 43
Likes: 0
From: ManchesTer
Default

Originally Posted by JoBy
It seems like someone did not like to change the light bulbs the correct way.




This is 1984 scematics but it should be similar. The big blue box is the insides of the turn indicator lever.
As you see the indicator lever selects between stop lamp signal and flasher relay. The hazard is also selected here.

To convert to 'export' you cut the white wire from the stop switch. Then you use the blue instead, same as third brake light to the brake light function. Old flash/brake is now only flash.

So your saying cut white wire at plug on stop switch do I have to cut blue and put it to plug where white wire goes or just cut white wire and leave the plug as it is ?

Thanks
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

10 Ugly Corvettes That We Still Kinda Love

 Joe Kucinski
story-1

Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

 Brett Foote
story-2

10 Things Every Corvette Owner Needs (2026 Edition)

 Michael S. Palmer
story-3

8 Most "Only Corvette Owners Understand" Quirks and Problems

 Pouria Savadkouei
story-4

10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

 Joe Kucinski
story-5

How Much Horsepower Every Corvette Engine "LOST" in 1972

 Joe Kucinski
story-6

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

 Michael S. Palmer
story-7

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

 Joe Kucinski
story-8

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

 Joe Kucinski
story-9

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

 Verdad Gallardo
Old Dec 7, 2018 | 08:56 AM
  #9  
JoBy's Avatar
JoBy
Melting Slicks
25 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2001
Posts: 2,150
Likes: 304
From: Timra, Sweden
Default

Your car is already converted as I understand. Do you want to make it work with the export lights, or convert back to original?

What I described with the schematics is how to convert from standard to export. You can see how that match with what is done in your car.
Export stop lights use the same cable as roof stop light. By cutting the white wire you remove stop signal from turning lights.
Reply
Old Dec 19, 2018 | 08:19 AM
  #10  
Simon Dickens's Avatar
Simon Dickens
Thread Starter
Intermediate
 
Joined: Nov 2018
Posts: 43
Likes: 0
From: ManchesTer
Default

Brake lights now working the white wire had been cut and a grey wire solder to the plug end which ran to the back of the car after much testing I found the wire from front to back had 3 breaks in it I think it must have got caught and yanked out

i re Instated it and now working the blue wire for the hi level switch has 4 volts on it I suspect the white block is a resistor as it's an led brake but I think the led has failed altogether I want to remove it to test the wiring and the lamp any pointers gratefully received thanks everyone for help merry Christmas to all 👍
Reply

Get notified of new replies

To Problem with brake lights





All times are GMT -4. The time now is 06:55 PM.

story-0
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-1
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE
story-2
10 Things Every Corvette Owner Needs (2026 Edition)

Slideshow: 10 great gifts Corvette enthusiasts actually want for Father's Day!

By Michael S. Palmer | 2026-06-03 15:43:40


VIEW MORE
story-3
8 Most "Only Corvette Owners Understand" Quirks and Problems

Slideshow: These are the quirks, annoyances, and oddly lovable problems that every Corvette owner eventually learns to live with.

By Pouria Savadkouei | 2026-05-28 09:31:39


VIEW MORE
story-4
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

Slideshow: 10 reasons why the C6 Z06 is still a performance benchmark after 20 years.

By Joe Kucinski | 2026-05-27 17:20:09


VIEW MORE
story-5
How Much Horsepower Every Corvette Engine "LOST" in 1972

Slideshow: How much horsepower every Corvette engine lost in 1972.

By Joe Kucinski | 2026-05-27 16:54:53


VIEW MORE
story-6
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-7
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-8
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-9
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