Recommended Custom Fit Brake Controller Harness for a 2006 GMC Sierra 2500  

Question:

Expert Reply:

Welcome back Chris! I'm a big fan of the Redarc Tow-Pro Elite item # RED63RR and I could go on all day about how great of a brake controller it is. Hidden main unit, uniquely small dash mounted knob, off-road settings, and active calibration. However, unless you're pulling multiple trailer's and you're wanting to program specific settings for each of them, I don't think you're going to gain much over your Voyager item # 39510. You can easily adjust the gain on the knob to dial in your brake settings.

The main reason you would have to upgrade to the Tow-Pro Elite item # RED63RR is if you're going to pull a trailer with electric over hydraulic brakes or EOH. The Voyager item # 39510 is only going to work with electric drum brakes.

The Tekonsha Plug-In Wiring Adapter item # 3015-P, is the custom fit harness you'll need to install both controllers in your 2006 GMC Sierra 2500. The harness plugs into a junction box under the dash to the left of your brake pedal. If you stretched your left leg out and rested it towards the firewall between the brake pedal and the e-brake your foot would be resting on the junction box. Or behind the clutch if your truck has the millennial anti-theft manual transmission!

Unless you're pulling a trailer with EOH brakes, I recommend using the Tekonsha Plug-In Wiring Adapter item # 3015-P to install your Voyager item # 39510 and see if you're comfortable with this controller in your Sierra. If you decide to upgrade, the adapter included with the Redarc Tow-Pro Elite item # RED63RR will plug directly into the item # 3015-P.

I attached a picture below on where to find the junction box, along with an installation video we did on a different controller but used the same harness.

What kind of trailer or trailers are you pulling?

You can add this information, along with any other questions you have, where it says Add Comment.

expert reply by: Jerred H

0

3015-P
(click to enlarge)

Chris

2/14/2026

Thanks for the reply We originally got the truck to pull a 2005 Keystone TT and that is how the Tekonsha is connected. It's always done great We just updated to a 2025 Cougar which is obviously a different experience. I do feel I often tweak the gain control between highway and around town so I wasn't sure if this would change that experience I think what you are saying is that the experience would be similar and not enough of a difference to justify upgrading my controller to the Redarc or probably another brand Thank you

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Jerred H.

2/14/2026

@Chris You're welcome! That's exactly what I am saying. The settings you can program into the Redarc Tow-Pro Elite item # RED63RR will help you with the gain adjustments between road and highway though. So if it is causing a distraction you know this option is out there. Congrats on the new trailer btw!

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Steve H.

2/15/2026

I have purchased the tekonsha brake controller as well as the tekonsha wiring adapter which all worked great with my 2007 lbz Duramax. Everything plugged right in the way it should and I do not have the issues with my trailer brakes locking up like my old module did. I pull a 2021 Grand Design 31’ and I have no complaints since upgrading with the tekonsha brake controller, Thanks Etrailer.com.

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