Trailer Light Test Returns to the myChevrolet & myGMC Apps

GM has quietly brought back a feature that a lot of truck owners asked for — the Trailer Light Test inside the myChevrolet and myGMC mobile apps.

If you tow regularly, this is one of those small updates that actually makes life easier.

What Is the Trailer Light Test?

The Trailer Light Test allows you to cycle your trailer lights directly from your phone, so you can stand behind the trailer and confirm everything is working — without climbing in and out of the cab.

The test runs through the following light functions in sequence:

• Brake lights

• Turn signals

• Reverse lights (if equipped)

• Running lights

If the truck detects a problem during the test, the system can alert you and help narrow down the issue.

Which Trucks Are Supported?

GM has re-enabled the feature on the following vehicles:

• Chevrolet Silverado 1500 / GMC Sierra 1500 — Model Years 2019–2026

• Chevrolet Silverado HD 2500/3500 / GMC Sierra HD 2500/3500 — Model Years 2020–2026

The feature is accessed through the Controls tab in the mobile app and is part of GM’s Remote Commands functionality.

Why This Matters (Especially for Diesel Owners)

Proper trailer lighting isn’t just a convenience — it’s a legal requirement and a major safety item when towing.

From a real-world perspective, this feature:

• Saves time during hook-up

• Helps catch wiring or ground issues early

• Reduces the chance of towing with inoperative lights

• Eliminates the “back-and-forth” between the cab and trailer

For owners towing boats, campers, or equipment with a 3.0 Duramax, this is one of those practical features that actually gets used.

What You’ll Need

• A compatible Silverado or Sierra

• The myChevrolet or myGMC app

• An active connected services plan

• A working trailer wiring connection

Availability and functionality can vary by vehicle configuration and service plan.