2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Brake lights don't come on, lights work, fuse OK

Thread Tools
 
Search this Thread
 
Old Mar 21, 2003 | 05:55 PM
  #1  
Rx-7Addict's Avatar
Thread Starter
Rotary Powered
Tenured Member 20 Years
iTrader: (2)
 
Joined: Sep 2001
Posts: 2,272
Likes: 1
From: Chicago, IL
Brake lights don't come on, lights work, fuse OK

My brake lights don't come on at all!

However, my taillights work perfectly. I checked the fuse in the driver's footwell, and it is fine. Any ideas? Is there some sensor.

Also, the center light doesnt come on while hitting the brakes. Is there a sensor or something I can check out?

thanks
-scott
Reply
Old Mar 21, 2003 | 08:07 PM
  #2  
HAILERS's Avatar
HAILERS
Tenured Member 10 Years
 
Joined: May 2001
Posts: 20,563
Likes: 27
From: FORT WORTH, TEXAS,USA
Brake pedal switch.
Reply
Old Mar 21, 2003 | 08:17 PM
  #3  
rotaryracer1's Avatar
Senior Member
Tenured Member 10 Years
iTrader: (1)
 
Joined: Dec 2001
Posts: 655
Likes: 0
From: Salt Lake City
it is probably your "brake light switch" it is on your brake pedal arm under the dash. mine went out twice. it is very easy to replace and it costs about $6 at your local parts place. good luck
Reply
Old Apr 5, 2003 | 02:14 AM
  #4  
DC350's Avatar
Rotor Head
Tenured Member 05 Years
 
Joined: Jan 2002
Posts: 1,966
Likes: 0
From: British Columbia
mine just went out as well. When i put pressure on the pedal i do not hear a little "Click" anymore I guess i'll have to get another one.

You dont have to get it from mazda?
Just a parts store?
Reply
Old Apr 5, 2003 | 02:51 AM
  #5  
silverFC's Avatar
Full Member
Tenured Member 05 Years
 
Joined: Mar 2003
Posts: 179
Likes: 0
From: The Colony Tx.
i had the same problem but it was my main switch in the dash
Reply
Old Feb 3, 2004 | 06:16 PM
  #6  
Gibenstein's Avatar
Rotary Enthusiast
Tenured Member 20 Years
iTrader: (2)
 
Joined: Aug 2003
Posts: 1,001
Likes: 0
From: San Antonio, Texas
Bump Im having this problem is there anything else anyone knows about this issue ?
Reply
Old Feb 3, 2004 | 06:29 PM
  #7  
Icemark's Avatar
Former Moderator. RIP Icemark.
 
Joined: Apr 2001
Posts: 25,896
Likes: 24
From: Rohnert Park CA
Either the brake light switch

or if it is a S4 it could be the brake circuit board in the CPU.

Test the switch, if it is fine, then replace the CPU or the circuit board (again only on S4 models). The brake light switch runs right to the brake lights on S5 models.

And I have both rebuilt CPUs and rebuilt brake light circuit boards for the CPU on my website.
Reply
Old Feb 3, 2004 | 06:34 PM
  #8  
Gibenstein's Avatar
Rotary Enthusiast
Tenured Member 20 Years
iTrader: (2)
 
Joined: Aug 2003
Posts: 1,001
Likes: 0
From: San Antonio, Texas
Are the horn and brake lights interconnected Icemark b/c I saw this post and I was wondering what you meant by it .

https://www.rx7club.com/showthread.p...t=brake+lights

Cuz my horn doesnt work either...
Reply
Old Feb 3, 2004 | 06:39 PM
  #9  
Icemark's Avatar
Former Moderator. RIP Icemark.
 
Joined: Apr 2001
Posts: 25,896
Likes: 24
From: Rohnert Park CA
Originally posted by Gibenstein
Are the horn and brake lights interconnected Icemark b/c I saw this post and I was wondering what you meant by it .

https://www.rx7club.com/showthread.p...t=brake+lights

Cuz my horn doesnt work either...
The Horn and Brake lights use the same fuse
Reply
Old Feb 4, 2004 | 08:13 AM
  #10  
Gibenstein's Avatar
Rotary Enthusiast
Tenured Member 20 Years
iTrader: (2)
 
Joined: Aug 2003
Posts: 1,001
Likes: 0
From: San Antonio, Texas
Is it dumb luck my horn and brake lights dont work ? Cause the "Stop" fuse looks good..
Reply
Old Feb 4, 2004 | 08:26 AM
  #11  
wai's Avatar
wai
RX7 club knows about you
Tenured Member 20 Years
 
Joined: Feb 2001
Posts: 201
Likes: 0
From: Honolulu Hawaii <--> Hong Kong
I had the same problem before,
I think you have to take out the cpu and resolder the brake part
Reply
Old Feb 4, 2004 | 10:25 AM
  #12  
Icemark's Avatar
Former Moderator. RIP Icemark.
 
Joined: Apr 2001
Posts: 25,896
Likes: 24
From: Rohnert Park CA
Originally posted by Gibenstein
Is it dumb luck my horn and brake lights dont work ? Cause the "Stop" fuse looks good..
Please meter the fuse or replace it with a known good fuse. If the ATF style fuse cracks (which some times happens when they get old) you won't be able to see it's blown/no good.

Also do the parking lights and headlights work? You could also have a bad 60 amp fuse under the hood if they don't.

Or is the CPU plugged in?
Reply
Old Feb 4, 2004 | 11:56 AM
  #13  
Gibenstein's Avatar
Rotary Enthusiast
Tenured Member 20 Years
iTrader: (2)
 
Joined: Aug 2003
Posts: 1,001
Likes: 0
From: San Antonio, Texas
All my lights work headlights , inside lights , park lights , reverse lights.... Its just the brake lights.
Reply
Old Feb 4, 2004 | 03:24 PM
  #14  
Icemark's Avatar
Former Moderator. RIP Icemark.
 
Joined: Apr 2001
Posts: 25,896
Likes: 24
From: Rohnert Park CA
sure sounds like the fuse then...
Reply
Old Feb 5, 2004 | 06:22 PM
  #15  
Gibenstein's Avatar
Rotary Enthusiast
Tenured Member 20 Years
iTrader: (2)
 
Joined: Aug 2003
Posts: 1,001
Likes: 0
From: San Antonio, Texas
Ok I just changed all the fuses work now... I fixed my clock like that yay !! But anyways no go on the brake lights. All my lights work I checked the switch and I am getting a reading out of it.. But I am not however getting a reading out of the wires for some strang reason ... Anyone help ?
Reply
Old Feb 5, 2004 | 07:12 PM
  #16  
Gibenstein's Avatar
Rotary Enthusiast
Tenured Member 20 Years
iTrader: (2)
 
Joined: Aug 2003
Posts: 1,001
Likes: 0
From: San Antonio, Texas
Bump does the CPU give signals to the wires on the brake light switch.
Reply
Old Feb 5, 2004 | 07:31 PM
  #17  
Icemark's Avatar
Former Moderator. RIP Icemark.
 
Joined: Apr 2001
Posts: 25,896
Likes: 24
From: Rohnert Park CA
On the S4 the wires feed from the fuse, to the brake light switch, to the CPU, to the lights.

So if you have a S4, the next step is to go to the CPUs bottom 4 pin plug and check if you are getting a brake switch signal there, and if so, if you are getting the output from the CPU to the lights.
Reply
Old Feb 6, 2004 | 01:03 PM
  #18  
HAILERS's Avatar
HAILERS
Tenured Member 10 Years
 
Joined: May 2001
Posts: 20,563
Likes: 27
From: FORT WORTH, TEXAS,USA
Here is a jpg of the stop light circuit. Why not pull the CPU plug and put a meter on the WG wire and see if you have 12v when you step on the brake pedal??? YOu do? Then jumper the WG to the G wire and step on the brakes. Go stop lights??? BAd CPU. Icemark will fix it for you.
Reply
Old Feb 6, 2004 | 01:07 PM
  #19  
Gibenstein's Avatar
Rotary Enthusiast
Tenured Member 20 Years
iTrader: (2)
 
Joined: Aug 2003
Posts: 1,001
Likes: 0
From: San Antonio, Texas
Will do it tommorow. I am thinking bad CPU relay b/c all of the other lights work perfectly so I will test it saturday when I am putting in my oil line. YAY !!
Reply
Old Feb 7, 2004 | 08:10 AM
  #20  
HAILERS's Avatar
HAILERS
Tenured Member 10 Years
 
Joined: May 2001
Posts: 20,563
Likes: 27
From: FORT WORTH, TEXAS,USA
Lets say it turns out to be the CPU. I think you could extract the Green/White wire and the Green wires from the connector and join them together (your favorite method) and have brake lights like a normal car. The CPU run seems to be just for a indication that you have a brake lite out. Otherwise the car should work like a normal car. You'd have to put some insulation lile electrical tape around the two wires connectors for obvious reasons.
Reply
Old Mar 15, 2004 | 03:01 PM
  #21  
HardDrive's Avatar
Full Member
Tenured Member 05 Years
 
Joined: Mar 2004
Posts: 70
Likes: 0
From: New Braunfels
Originally posted by HAILERS
Lets say it turns out to be the CPU. I think you could extract the Green/White wire and the Green wires from the connector and join them together (your favorite method) and have brake lights like a normal car. The CPU run seems to be just for a indication that you have a brake lite out. Otherwise the car should work like a normal car. You'd have to put some insulation lile electrical tape around the two wires connectors for obvious reasons.

Well I dont know if its a good idea or not to hook it up that way, I dont see why not at this point. But that does work.
I just checked mine cause I was haveing the same problem, only my blinkers and my brake lights where the ones not working while everything else was fine.
Brake lights are the CPU, Blinkers however I am not sure but am thinking the contacts in the switch might be funcky cause after i hit my head on the streering wheel they work again.
Reply
Old Mar 16, 2004 | 05:14 PM
  #22  
harley71105's Avatar
Senior Member
Tenured Member 10 Years
 
Joined: Mar 2004
Posts: 435
Likes: 0
From: Shreveport, Louisiana
Yep

That happened to me on one of my 88's about three or four years back....down on the floor to the left of your left foot next to the firewall and fusebox is a "CPU" ...
now this is not the ECU or main computer but the CPU...
it is a black plastic box and contains the circuit for the brake lights and two other circuits....you have to replace the whole thing unless you know someone who can repair electronic circuits...a new one is $450 but I got mine from an online salvage place for $50 so I bought two of them....I would wager this is your problem too...I replaced bulbs, fuses, brake pedal switch....then found this out...good luck...dude...
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
trickster
2nd Generation Specific (1986-1992)
25
Jul 1, 2023 04:40 PM
torky007
3rd Generation Specific (1993-2002)
7
Aug 17, 2015 05:14 PM
Sharkbait24
New Member RX-7 Technical
1
Aug 12, 2015 10:36 AM




All times are GMT -5. The time now is 01:56 PM.