Installing Trailer Wiring and Brake Controller on a 2018 Chevy Express 3500

Updated 07/28/2025 | Published 06/08/2020

Products Featured in This Question

Tekonsha Primus IQ Trailer Brake Controller - Up to 3 Axles - Proportional

(2142)

$94.34

Deka Jacketed 2 Wire, 10 Gauge, Brake Wire - per Foot

(321)

$3.40

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(452)

$33.94

Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires

(3330)

$124.35

7- and 4-Pole Trailer Connector Socket w/ Mounting Bracket - Vehicle End

(2590)

$41.24

Question:

I am installing a hitch and wiring for trailer towing on my daughters 2018 Chevy Express 3500, 15 passenger van. It does not have a tow package but does have an 8 pin rectangle plug at the rear on the inside rail. it looks just like the ones shown in the Arcadia and traverse demo videos. How do i know if it is the trailer wiring connector so that i can order the #118271 kit with confidence. Also, if so does the kit provide fuse and relay placement and wiring installation information for this vehicle? Also how do i know if there is a break controller wire connector under the dash? Thank you for taking the time for an answer.

asked by: David H

Helpful Expert Reply:

I'm not sure what that 8-pin plug on your daughter's 2018 Chevy Express Van 3500 is, but I can say that is definitely not something used for trailer wiring.

Since the Express Van didn't come with the factory tow package 7-Way you'll want to look for a frame pocket on the driver side rear left corner of the frame for a seven-wire harness with the connector that you should be able to install wiring with a US round connection, like the Hopkins # HM40975, to. If you can't find that wiring then you'll need to install the T-One # 118392 as well as the Wiring Kit # ETBC7 and additional wiring # 10-2-1. This will give you everything you need to install a brake controller.

If you find that connector in the frame rail then you'll have a 4-wire harness under the dash which should have some labels:

Black: Ground
Red/White: Battery Feed
Dark Blue: Trailer Brake Signal
Light Blue: CHMSL/Stoplamp Supply Voltage

For a brake controller I recommend the Tekonsha Primus IQ # TK90160. If you have the OEM wiring then you'll just need to splice the pigtail to your existing wiring, but if you don't then you'll need to use some of the wiring from the ETBC7 kit to complete the installation. Either way you'll connect the pigtail from the Primus IQ to the following function:

Blue - 7-Way Output to Trailer
Black - 12V Power
White - Ground
Red - COLD Side of Stop Light Switch (only gets hot when brake pedal is pressed)

Let me know if you have any questions and I'll be more than happy to help you figure this out!

expert reply by: Jon G

Rick

7/28/2025

Hello John I have a 2018 Chevrolet Express van 2500 underneath the floorboard in the driver side there is wires that appear to be for the brake actuator to activate the electric brakes however there are no fuses in the fuse box for that wire can I use those wires to supplement my installation to the back of the van or is they going to be useless and how should I proceed with installation do you have a video that can help me with that process thank you very much Rick Navarro

Jon G.

7/28/2025

@Rick You'll need to find 4 wires that have the functions I referenced above. We actually do have an installation video of the Universal Wiring Kit # ETBC7 on a 2018 Express that I'm linking to this comment for your reference.

Helpful Links

tv-install-etrailer-universal-brake-controller-installation-kit-2018-chevrolet-express-van-etbc7.aspx