Brake Control Connection Can Shut Down Brake Light System

Technical Bulletin

Problem with Brake Control Installation in 2005-2007 Chevrolet Uplander, Pontiac SV6, Buick Terraza and Saturn Relay

SUMMARY: Connecting a brake control system in these vehicles in a certain way will shut down the brake light system.

PROBLEM: These vehicles use a multiplex system in their wiring. If you connect a brake control to the "cold side" of the brake light switch, it will shut down the brake light system.

SOLUTION: The brake light switch sends an input to the Body Control Module (BCM), which activates the high mount stop lamp. The wire that operates the high mount stop lamp can be used to activate the brake control. Connecting to this wire will not have any effects on the BCM, according to GM. The signal for the Red wire (on the brake controller) can be obtained at the BCM. The BCM is located just under the front of the dash on the left side, just above your left knee as you are seated in the driver's seat.

Custom Fit Brake Controller

Brake Controller Mechanism Viewed from the Floor Image

Fig. 1. BCM as seen from the floor, looking up under the dash. On the very bottom of the BCM you will find a 52-pin connector. The label on the bottom can identify the BCM. On this label will be the acronym VBCM. The 52-pin connector will have a Green locking clip. In the center of this 52-pin connector you will find a White wire. This wire is the high mount brake light wire.

52-pin connector with green locking clip and white wire Image

Fig. 2. The 52-pin connector, green locking clip and white wire on BCM. This White wire is in Pin Location 30. This wire will have 2.5 volts with the key in the "run" position, even though the brake pedal is not applied, and will go to 12 volts when the brake pedal is applied.

Fig. 3. BCM with 52-pin connector on bottom, green locking clip.

Manufacturer: Cequent

Bulletin Date: 7/21/05

Bulletin Number: 09-0110

Updated By: Dani S.

Last Updated: 3/8/2021

Explore Expert Info

on Trailer Brake Controller

Videos

for Trailer Brake Controller

Help Articles

for Trailer Brake Controller

Expert Answers

for Trailer Brake Controller

Choosing the Right Trailer Wiring

Trailer Brake Controller Installation - 2014 Jeep Grand Cherokee

Trailer Brake Controller Installation - 2015 Jeep Grand Cherokee

Choosing the Right Brake Controller

Tow Ready 4-Pole Mounting Bracket Installation

Redarc Tow-Pro Liberty Brake Controller Review

Tekonsha Prodigy P3 Trailer Brake Controller Review

Choosing Between Tekonsha Brake Controllers

Review of etrailer - Brake Controller - ETBC7

Curt Echo Mobile Trailer Brake Controller Review

Redarc Tow-Pro Trailer Brake Controller Plug-and-Play Wiring Harness Review

etrailer Trailer Brake Controller Universal Kit Review

Brake Controller 7- and 4-Way Installation Kit (ETBC7)

Trailer Wiring Diagrams

Brake Controller Installation: Starting from Scratch

Tech Bulletin: Redarc Tow Pro Liberty - 2018+ Toyota 4Runner

How to Choose the Right Trailer Hitch Class

My Trailer Hitch Doesn't Fit

How to Measure for Trailer Hitch Drop

Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)

5 Things to Know About Weight Distribution Hitches

Towing a Trailer? Let's Talk About Brake Controllers

Determining Trailer Tongue Weight

Best Bike Racks for Electric Bikes

Is Curt Echo Brake Controller a Quality Brake Controller Solution

We've had overall incredible results so far with the Curt Echo Mobile Brake controller part #C51180. We've sold quite a few and haven't really had any negative feedback to report. I'd be shocked if you had an issue,…

view full answer...

Wireless Brake Controller - Curt Echo vs Tekonsha Prodigy RF

The best option for wireless brake controllers is the Curt Echo #C51180. It is the easiest to plug in and go when you need to use a brake controller with your trailer. Once you have a 7-way connector installed in your vehicle, all you need is to…

view full answer...

Brake Controller Recommendation for 2016 Toyota Highlander

For a brake controller I would recommend the Prodigy P3 Brake Controller part #90195 for your 2016 Toyota Highlander. This is our best selling brake controller because of how well it works and how easy it is to setup. This is a proportional brake…

view full answer...

Can Trailer Brake Controller Be Installed on 2019 Toyota Highlander

You can absolutely install a trailer brake controller on your 2019 Toyota Highlander and I will happily go through all the parts you will need for this. To start, if the Highlander isn't already equipped with one, you will need to add a 4-Way…

view full answer...

Recommendation For Brake controller For 2010 Toyota Highlander Towing 3,000-lb Single Axle Camper

Based on your information, I recommend the Tekonsha Prodigy P3 Brake Controller, Item #90195, for you 2010 Toyota Highlander Limited. It is a proportional controller with an LCD display, storable settings, 3 boost levels, runs continuous diagnostics,…

view full answer...

Is a Brake Controller Needed for a 2019 Toyota Highlander

It would be a good idea to use a brake controller while towing with a 2019 Toyota Highlander especially if the trailer is setup for them. That said, it may or may not be required. There are certain laws and regulations for this which vary by state. I…

view full answer...

Which Way Should Diode Point on Highlander for Install of Brake Controller

Yes you need the diode arrow to point towards the brake controller. That will allow the voltage to travel into the controller but not backfeed back on to the Highlander in any way. If you need a diode we have the part #RM-690.

view full answer...

How to Find COLD Side of Brake Light Switch for Hardwiring Brake Controller

When you are hardwiring a trailer brake controller like the Prodigy P2 #90885 the red wire connection that provides the triggering signal to the controller should be made to the wire on the COLD SIDE of the brake light switch circuit. This is the…

view full answer...

What is the Difference Between a Class II and a Class III Hitch?

The difference between the Class II and Class III hitches has to do with their Gross Trailer Weight (GTW), their Tongue Weight (TW), and their Hitch Receiver Size. Class II trailer hitch receivers have a 1-1/4 inch receiver and can be rated up to…

view full answer...

What is the Difference Between a 4-Way and 7-Way Trailer Connector

A 4-Way trailer connector has the basic lighting functions only; running lights, left turn signal and brake lights, right turn signal and brake lights, and ground. A 7-Way has these functions and a 12 volt circuit, a circuit for electric trailer…

view full answer...

What is the Difference Between the Tekonsha Prodigy P2 and the P3 Brake Controllers

Actually, the P3 now has the upgraded axis accelerometer like the P2. The Tekonsha P3 Trailer Brake Controller #90195, will work with both electric over hydraulic brakes on the trailer as well as electric brakes. It has a menu option on the display…

view full answer...

Difference Between Curt and etrailer Trailer Hitch Receivers for 2020 Chevy Colorado

There is only one difference between the Curt Trailer Hitch Receiver #C13176 and etrailer Trailer Hitch Receiver #e98909 that fit your 2020 Chevrolet Colorado, which is the finish. The Curt trailer hitch has a glossy black finish while the etrailer…

view full answer...

Contact & Help

What our customers are saying:

"I like the easy of navigation through the site. It only took me a couple of minutes to place my order. Thank You I will shop this sight again in the future."

Kevin

Manchester, MD