If the “Service Trailer Brake System” message appears on your truck dashboard, it
could indicate wire or module issues that could result in serious accidents or damage
to both vehicle and trailer. Do not ignore this error code as doing so could put lives
at risk and lead to costly repairs for both.
Step one is to disconnect the brake controller so no electricity or power will flow
through it. If yours is hardwired, cut its output wire where it connects between it and the trailer.
Integrated Trailer Brake Controller
GMC Sierras come equipped with factory tow packages that make installing a trailer
brake controller simple. A plug-in wiring harness sits beneath the dashboard where a
brake controller would normally go; simply unplug it to stop power from reaching it and switch it off!
Integrated Trailer Brake Control (ITBC) was designed to detect issues with various
components associated with trailer brakes and generate codes to help identify
where they lie; however, some vehicle owners have reported that these codes never appear.
Error message “Service Trailer Brake System” indicates a problem with your ITBC,
potentially due to module or wiring issues disconnecting it from its power source.
For your own safety, professional help should be sought immediately in order to
diagnose and resolve this issue as soon as possible so you can continue safely
driving both truck and trailer until everything has been addressed.
Brake Pressure Sensor
Brake pressure sensors are part of an integrated trailer brake controller (ITBC).
When detected as malfunctioning by ITBC, they will illuminate their warning light
and set DTC as well as temporarily disabling ESC for ignition cycle duration as a
safety measure; once DTC has been cleared away again, ESC will reactivate.
In such an instance, an ITBC could potentially encounter issues in its wiring or
module that obstruct power being sent to trailer brakes – this poses a serious safety
risk and should be resolved as soon as possible before driving any further.
To solve this issue, the easiest solution is to disconnect your brake controller.
However, if your trailer brakes are hardwired to it and cannot be disconnected
without cutting output wires somewhere between it and the trailer – after which,
reconnecting should reset service trailer brake system message.
Relay
While you could drive your GMC Sierra when its dashboard displays the Service
Trailer Brake System error message, doing so would not be safe. This message
indicates something is amiss with its integrated trailer brake controller wiring or
module; although its rear trailer connection may still work fine for now. Therefore, as
soon as this issue arises it should be resolved immediately.
First step to solving this problem: unplug the brake controller by using a flathead
screwdriver to loosen its locknut. Once disconnected, cut output wire between brake
controller and trailer; this will cut power supply to brake controller while also
stopping it from receiving signals from trailer. As an alternative solution, replace
fuse INT PRK 10AMP located within instrument fuse box – however this should only
be considered temporary measure.
Fuse
The trailer brake controller utilizes the momentum of your truck decelerating to slow
and stop your trailer, providing an alternative to surge brakes which may be less
responsive and require more effort. Unfortunately, when these systems have issues
they can lead to accidents and damages; one telltale symptom being seeing an error
message on your dashboard regarding service trailer brake system errors which
indicate there may be something blocking electricity from flowing from vehicle to trailer.
Resetting the trailer brake system on your GMC Sierra doesn’t need to be
complicated; all it requires are a few tools and some spare time at home. Make sure
that a flathead screwdriver and hammer are available, plus an assistant who can
assist in this work.