Troubleshooting After Market Light Bar Causing Error Codes On My Dashboard Of My GMC
Updated 11/04/2025 | Published 09/30/2025
Question:
I had an aftermarket tailgate light bar installed on my 2019 GMC Sierra AT4 by a professional. It is wired in the existing wiring. The light bar works but I am getting 6 alerts on my dashboard ie: check left turn signal, check right turn signal, check this, check that, ETC. My local GMC service center will not touch it due to miles over 150,000. The GMC rep I did talk to said that I will not need it to be programmed. Any reason why I am constantly getting the alerts on my dashboard? The alerts come on upon engine start. I dismiss all the alerts. Upon braking or turn signaling the alerts go off again. The person who installed the light bar doesnt understand why it is doing this. I found your YOUTUBE video of installing light bars. I was wondering if you have heard of this issue with GMC trucks or can help me with this issue. Thank you for any help you can provide. Rick Atlanta Ga.
asked by: Rickey R
Expert Reply:
Hey Rickey,
I have not heard of that issue too often but I have seen similar experiences before. The most likely cause in my opinion is the difference in power draw between the light bars bulbs and your vehicles originally. Most likely your truck has incandescent bulbs and the light bar has LED lights. The lower power draw from the LED lights almost mimics that of a burnt or bad bulb. The best fix for that is adding a load resistor in between the light bar and factory wiring.
Do you remember what brand or model light bar you installed? I can see if there is a load resistor specifically for that light bar to make things easy for you.
Product Page this Question was Asked From
Rampage SuperBrite LED Tailgate Light Bar - Stop, Tail, Turn - 4-Pole Flat - 60" Long
- Vehicle Lights
- Accent Light
- Tailgate Bar
- Single Light
- LED Light
- Light Assembly
- Strip
- Red/White
- Rampage
more information >
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Nick S.
10/30/2025
Hey Rick, did adding a load resistor help clear those dashboard alerts on your Sierra? Knowing how that fix worked could really help others running LED light bars on similar trucks.