How to Fix the Service Trailer Brake System Message on Your Dashboard

Your dashboard’s “Service Trailer Brake System” message indicates there may be an
issue with the electronic braking system connected to your trailer, possibly caused
by disconnection in its wiring or defective module or relays.

Begin by locating and loosening the adjustment nut located at the rear of your trailer
brake with a flathead screwdriver.

Check the Brake Fluid

Your trailer brakes are essential to safe towing, ensuring that it can stop when
needed. However, sometimes they can start having issues and produce a warning
message on your DIC display screen. Luckily, there are various steps you can take to
rectify the situation and get your trailer up and running again.

At first, it’s important to identify why this message is popping up – this could be
caused by anything from an intermittent wire connection to a defective brake
controller switch – in order to effectively address it and potentially avoid an accident while driving.

One common cause of brake controller switch or fuse problems is a defective unit
rated 30 amps or above; replacement should be straightforward. Furthermore,
cleaning connections at 7-way connectors with dielectric grease is advised in order
to minimize potential issues in future.

How to Fix the Service Trailer Brake System Message on Your Dashboard

Check the Connections

Connections in a trailer brake system may not always be in great shape and could
easily be the source of an illuminated service trailer brake light. Corroded or
improperly formed connections may result in issues like not accepting signals from
tow vehicles and shorted magnet coils on controllers, leading to service trailer brake lights coming on.

Checking connections may be the solution to this problem quickly and efficiently.
First, ensure the park lamp fuse identified as INT PRK 10amp hasn’t blown – this
would trigger alert mode on your system and could result in costly repairs to rectify.

Once you have located and replaced the fuse, remove and reinstall it with another.
Re-check all connections to the trailer connector and 7-way receptacle for looseness
or corrosion and apply dielectric grease as necessary. If the problem still exists, visit
your dealership who may replace either TBCM, EBCM or Brake Pressure Sensor as
part of their diagnostic tests.

Check the Wiring

Finding this message on your dashboard indicates a serious issue with the trailer
braking system, which if left unaddressed could lead to serious accidents and
damages to both vehicle and trailer. If left unaddressed it could result in fatal
accidents as well as major repairs costs for both.

Typically, this warning message indicates that the ITBC (Integrated Trailer Brake
Controller) has become disconnected from its power supply due to either wiring
issues or module malfunction. This impedes its proper functioning and must be
resolved as quickly as possible for it to function normally again.

First, using a star wheel adjuster or flathead screwdriver, remove the locknut from
the ITBC’s adjusting nut. Next, turn clockwise until it snugly rests against its backing
plate – once tightened it should allow free wheeling again. Other electrical issues
could also be the source of this message appearing on your dashboard; so check
fuses and wiring areas thoroughly as well as coating all connections with dielectric
grease for additional peace of mind.

Check the Switch

This message may appear when there is an issue with the trailer brake module or
wiring that prevents electricity from flowing between your truck and trailer. Should
this be the case, be sure to address it quickly to avoid serious accidents or damages
to both your vehicle and trailer.

One of the primary sources of this error message is a blown fuse. Replacing it is an
easy solution that will save money on mechanic costs.

One other possible reason could be low voltage from your battery. This is easily
verified using a multimeter; if it falls below normal range, get it checked more
closely by an experienced mechanic.

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