How to Fix a GMC Sierra 1500 Brake Light Fault

By Nick Marchenko, PhD

Greetings, DIY enthusiasts and truck lovers! Today, we're diving into a common yet pesky issue that many GMC Sierra 1500 owners might encounter: a brake light fault. No need to stress, though! I'm here to guide you through the process of identifying and fixing this problem in your beloved GMC Sierra 1500, all in your own garage.

Step 1: Check the Brake Light Fuses

First things first, let's start with the basics. A blown fuse is often the culprit behind brake light issues. So, pop open your GMC Sierra 1500's fuse box. It's usually located under the hood or near the driver's side dashboard. Consult your owner's manual if you're unsure. Look for the fuse that controls the brake lights. If it's blown, replace it with a new one of the same amperage.

Shop From Amazon

340 Pcs Assorted Standard & Mini & Low Profile Mini Auto Car Truck Blade Fuses Set- 2A 5A...

CrocSee 250 Pieces - Car Fuses Assortment Kit, Blade-Type Automotive Fuses - Standard & Mi...

Nilight 372 PCS Car Fuses Assortment Kit Standard Mini LP Mini Micro2 Blade Fuse ATO ATC A...

Step 2: Inspect the Brake Light Bulbs

Sometimes, the solution is as simple as changing a bulb. To check the brake light bulbs, you'll need to access the back of the brake light assembly. This can usually be done by removing a few screws or bolts. Once you have access, inspect the bulbs. If they're dark, cloudy, or broken, it's time for a replacement. Make sure to get the correct type of bulb for your GMC Sierra 1500.

If you notice that the bulb looks unusual, or if it shows signs of wear or damage, it should be replaced. If you don't know which bulb to replace it with, check out our bulb size chart:

• 2020 GMC Sierra 1500 Light Bulb Sizes;
• 2019 GMC Sierra 1500 Light Bulb Sizes;
• 2018 GMC Sierra 1500 Light Bulb Sizes;
• 2017 GMC Sierra 1500 Light Bulb Sizes;
• 2016 GMC Sierra 1500 Light Bulb Sizes;
• 2015 GMC Sierra 1500 Light Bulb Sizes;
• 2014 GMC Sierra 1500 Light Bulb Sizes;
• 2013 GMC Sierra 1500 Light Bulb Sizes;
• 2012 GMC Sierra 1500 Light Bulb Sizes;
• 2011 GMC Sierra 1500 Light Bulb Sizes;
• 2010 GMC Sierra 1500 Light Bulb Sizes;
• 2009 GMC Sierra 1500 Light Bulb Sizes;
• 2008 GMC Sierra 1500 Light Bulb Sizes;

Step 3: Test the Stop Light Switch

If the fuses and bulbs look good, the next suspect is the stop light switch. This little gadget is responsible for activating your brake lights when you press the pedal. To test it, locate the switch near the brake pedal. You might need to remove a panel or two to get there. With the ignition on, use a multimeter to check if the switch is functioning correctly. If it's faulty, it's time for a replacement.

Step 4: Replace the Stop Light Switch

Replacing the stop light switch is a straightforward task, but it requires some attention to detail. First, disconnect the battery to avoid any electrical mishaps. Locate the switch, unplug it, and unscrew it from its position. Replace it with a new one, ensuring it's properly aligned and secured. Reconnect the battery, and voila, you should be good to go!

Final Thoughts

Remember, working on your GMC Sierra 1500 can be both rewarding and a great way to save some cash. Always double-check your work, and if you're ever in doubt, don't hesitate to consult a professional. Safety first, folks!

Stay tuned for more DIY truck tips and tricks. Until next time, keep those wrenches turning!

See also:

• How To Replace Headlight Bulb On 2015 GMC Sierra;

Nick Marchenko, PhD

Industrial Engineer & Automotive Content Specialist

Nick writes in-depth guides on car clubs, engine specs, vehicle ownership, and modifications, combining engineering knowledge with automotive passion.

Full profile → LinkedIn →