Adding a 3rd Brake Light to a '67 - Page 3 - Chevelle Tech
Electrical & Wiring Troubleshooting electrical problems.

 23Likes
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #31 of 92 (permalink) Old Jan 13th, 19, 12:23 AM
Gold Member
Joe
 
Join Date: Aug 1998
Location: Lincoln, NE
Posts: 4,468
Re: Adding a 3rd Brake Light to a '67

Quote:
Originally Posted by paul bell View Post
I'd love to be proven wrong. Maybe somebody here will buy one and try it.

Before I installed my interior last year, I put a few wires into the plastic wireway for future stereo use. Ran from the dash to the trunk. I used one of those wires to feed my third light so I don't need to fool with these devices.

Paul, I guess you’ve never heard of a silicon controlled rectifier?

It’s a simple circuit.

But I digress.

As far as simplicity and long-term reliability, the best solution is running a dedicated wire back to the brake lamp switch.

Install a switch meant for an 1986 Monte Carlo for example. The extra contacts will allow for the operation of the 3rd brake lamp properly.

If you simply splice into the factory switch, then you will get unwanted backfeed—activating the 4-way hazards will cause a flashing 3rd brake light—which is against FMVSS rules (which I know know one here probably cares). (Not to be confused with a timed pulsing 3rd brake lamp during initial braking).

-If you don't stand for something, you'll fall for anything.
Coppertop is offline  
Sponsored Links
Advertisement
 
post #32 of 92 (permalink) Old Jan 13th, 19, 12:45 AM
Senior Tech Team
 
Join Date: Sep 2012
Location: New York City
Posts: 1,573
Re: Adding a 3rd Brake Light to a '67

Yessir, but a SCR would need a circuit to control it. These "converters" don't require steady power-or even a ground.

I never heard of a third light direct to the brake switch causing a feedback. I'll put an incandescent lamp on mine and see what happens. As I plan to use an LED strip, I'd think feedback would be nil.

LS1tech.com supermoderator.
How may I help you?
1971 Monte Carlo SS454-496ci 600hp
1999 Trans Am-500hp
2003 Iszu Ascender XL Limited V8
paul bell is offline  
post #33 of 92 (permalink) Old Jan 13th, 19, 12:29 PM
Gold Member
Joe
 
Join Date: Aug 1998
Location: Lincoln, NE
Posts: 4,468
Re: Adding a 3rd Brake Light to a '67

Quote:
Originally Posted by paul bell View Post
Yessir, but a SCR would need a circuit to control it. These "converters" don't require steady power-or even a ground.

I never heard of a third light direct to the brake switch causing a feedback. I'll put an incandescent lamp on mine and see what happens. As I plan to use an LED strip, I'd think feedback would be nil.
Paul,

The 3rd brake lamp doesn’t cause the feedback.

The term that really should be used is “backfeed”. If you simply tie the 3rd brake lamp (whether it is an incandescent unit or an LED unit) to the white wire on the brake pedal switch, the moment you activate your 4-way hazards, you have a backfeed of power on the white wire—so your 3rd brake lamp will also be flashing. This is a no-no in the automotive industry.

Also, I think you need to review this published circuit I have attached. This provides 3rd brake lamp operation with no dedicated power or ground connection to said “module”.

But again, for those reading this, your best choice is running a dedicated line back to a more modern brake lamp switch set-up for proper operation.
Attached Thumbnails
Click image for larger version

Name:	8204CD70-E667-4481-8EA6-5636E9EF641A.jpeg
Views:	12
Size:	72.8 KB
ID:	583274  
paul bell likes this.

-If you don't stand for something, you'll fall for anything.
Coppertop is offline  
 
post #34 of 92 (permalink) Old Jan 13th, 19, 1:14 PM Thread Starter
Lifetime Premium Member
Rick
 
Join Date: Sep 2018
Location: South Jersey
Posts: 120
Garage
Re: Adding a 3rd Brake Light to a '67

This is great information, thanks everyone. I'm going to use an '86-'88 Monte Carlo brake ligjt; I think I'll get a corresponding '86 brake light switch to avoid any issues. It sounds like the switch won't care whether I use an incandescent 1156 or an LED bulb.
fr8dog likes this.
Rickles is offline  
post #35 of 92 (permalink) Old Jan 13th, 19, 1:26 PM
Senior Tech Team
 
Join Date: Sep 2012
Location: New York City
Posts: 1,573
Re: Adding a 3rd Brake Light to a '67

Hey Rick, is the device from American Technology Components internally wired as the diagram you showed?

LS1tech.com supermoderator.
How may I help you?
1971 Monte Carlo SS454-496ci 600hp
1999 Trans Am-500hp
2003 Iszu Ascender XL Limited V8
paul bell is offline  
post #36 of 92 (permalink) Old Jan 13th, 19, 1:37 PM Thread Starter
Lifetime Premium Member
Rick
 
Join Date: Sep 2018
Location: South Jersey
Posts: 120
Garage
Re: Adding a 3rd Brake Light to a '67

Sorry, the diagram wasn't mine; I only had the picture with the wiring label. I don't know what's inside.
Rickles is offline  
post #37 of 92 (permalink) Old Jan 13th, 19, 3:30 PM
Senior Tech Team
 
Join Date: Sep 2012
Location: New York City
Posts: 1,573
Re: Adding a 3rd Brake Light to a '67

Rick, it looks like the one you posted a pic of is their AT-LC-1 logic and it's been replaced with the AT-LC-4, which has a additional terminal for a ground.

If they're description is accurate, if you have a turn signal on then step on the brakes, it will sense both then latch the third light output to on. It'll latch and hold on the output until BOTH light inputs are off.

In other words, once latched, it'll maintain the third light output even though one input is flashing.

I'm not sure how or what the circuitry is but it's worth a try.


The only slight issue is that if a flashing turn signal is on when you let go of the brake pedal, the third brake light may stay on until the flashing light is off between flashes. This could delay the third brake light from going out for a second or so. This wouldn't bother me.
Attached Thumbnails
Click image for larger version

Name:	AT-LC-4.JPG
Views:	29
Size:	190.5 KB
ID:	583286  

LS1tech.com supermoderator.
How may I help you?
1971 Monte Carlo SS454-496ci 600hp
1999 Trans Am-500hp
2003 Iszu Ascender XL Limited V8
paul bell is offline  
post #38 of 92 (permalink) Old Jan 13th, 19, 3:42 PM Thread Starter
Lifetime Premium Member
Rick
 
Join Date: Sep 2018
Location: South Jersey
Posts: 120
Garage
Re: Adding a 3rd Brake Light to a '67

He told me they tried the four-wire one but this three-wire is actually an update to the four-wire. According to him, this three-wire is the one to use for a '67.
paul bell likes this.
Rickles is offline  
post #39 of 92 (permalink) Old Jan 13th, 19, 3:51 PM
Senior Tech Team
 
Join Date: Sep 2012
Location: New York City
Posts: 1,573
Re: Adding a 3rd Brake Light to a '67

You gonna order it?

LS1tech.com supermoderator.
How may I help you?
1971 Monte Carlo SS454-496ci 600hp
1999 Trans Am-500hp
2003 Iszu Ascender XL Limited V8
paul bell is offline  
post #40 of 92 (permalink) Old Jan 13th, 19, 4:12 PM Thread Starter
Lifetime Premium Member
Rick
 
Join Date: Sep 2018
Location: South Jersey
Posts: 120
Garage
Re: Adding a 3rd Brake Light to a '67

I think I'll go with the wire to the brake light switch and get a new one for an '86 Monte.

.
Rickles is offline  
post #41 of 92 (permalink) Old Jan 14th, 19, 7:04 PM
Tech Team
 
Join Date: Sep 2010
Location: colorado
Posts: 679
Garage
Re: Adding a 3rd Brake Light to a '67

So, where are with this third brake light? I'm interested and have ordered the $6 strip and need to wire it up. The third wire up to the brake light switch, is a 3 wire switch needed or can I piggyback onto the white wire?

66 SS-396/425 - M22 -3:73 -12 bolt
USN-SSBN 645-G
boyd66k20 is offline  
post #42 of 92 (permalink) Old Jan 14th, 19, 11:02 PM
Senior Tech Team
 
Join Date: Sep 2012
Location: New York City
Posts: 1,573
Re: Adding a 3rd Brake Light to a '67

Quote:
Originally Posted by boyd66k20 View Post
So, where are with this third brake light? I'm interested and have ordered the $6 strip and need to wire it up. The third wire up to the brake light switch, is a 3 wire switch needed or can I piggyback onto the white wire?

I won't get to test it until this weekend.

LS1tech.com supermoderator.
How may I help you?
1971 Monte Carlo SS454-496ci 600hp
1999 Trans Am-500hp
2003 Iszu Ascender XL Limited V8
paul bell is offline  
post #43 of 92 (permalink) Old Jan 15th, 19, 9:48 AM Thread Starter
Lifetime Premium Member
Rick
 
Join Date: Sep 2018
Location: South Jersey
Posts: 120
Garage
Re: Adding a 3rd Brake Light to a '67

Keep us posted, Paul.

.
Rickles is offline  
post #44 of 92 (permalink) Old Jan 25th, 19, 8:24 AM
Tech Team
 
Join Date: Sep 2010
Location: colorado
Posts: 679
Garage
Re: Adding a 3rd Brake Light to a '67

Well, the led strips just don't seem to look right on a 60's car no matter where you put them. Yes, it would be nice to have more awareness back there. Is the monty third brake light an led type. I would be just as happy with third brake light that doesn't have to be LED. The led seems to pimp the ride out too much. What's the vote count , for or against?

66 SS-396/425 - M22 -3:73 -12 bolt
USN-SSBN 645-G
boyd66k20 is offline  
post #45 of 92 (permalink) Old Jan 25th, 19, 8:47 AM
Senior Tech Team
 
Join Date: Sep 2012
Location: New York City
Posts: 1,573
Re: Adding a 3rd Brake Light to a '67

Sorry, I got to my shop a few days ago and forgot to report.

Connected to the orange wire at the brake switch, an incandescent lamp comes on and stays on with the brake pedal pressed. It's unaffected by turn signal use. It flashes when the 4-way flashers are turned on. I like that.

The LED strip works the same as the incandescent. It's not as brilliant as I'd like it to be. I may use two-or a different one.

LS1tech.com supermoderator.
How may I help you?
1971 Monte Carlo SS454-496ci 600hp
1999 Trans Am-500hp
2003 Iszu Ascender XL Limited V8
paul bell is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in










Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome