Is Relay Required to Install Wiring Harness in 2018 Acura MDX

Published 03/07/2019

Products Featured in This Question

etrailer Trailer Hitch Receiver - Custom Fit - Matte Black Finish - Class III - 2"

(1678)

$179.97

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

(144)

$70.07

Question:

I am considering the Tekonsha wiring harness # 118628 which fits my 2018 MDX. In your QandA’s on the harness, you say: “Please note that with either harness it may be necessary to see a local Acura dealer for a relay. The relay is needed to activate the tow package wiring circuit.” Why does it say “may” be required? Sounds like it IS req’d. The Acura OEM trailer hitch assembly drawing does show a COUPLE of relays: P.N. 39794-SDA-A03 for $36.02 each?. Are two relays really required to activate tow pkg wiring? Where are they installed? Rear compartment where your kit plugs in, or possibly under the hood or instrument panel? Has your shop installed them? Anything else I would need to know? I’ve watched your video, and it looks pretty simple, but it doesn’t address the relay installation. Thanks

asked by: Doug B

Helpful Expert Reply:

The note you are referencing in regard to the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118628 specifically says the relay is "needed" so it is required in order to activate the tow package on your 2018 Acura MDX. The reason it may be necessary to see your Acura dealer is because your vehicle may or may not have the relay.

The relays are required to activate the tow package and it looks like this relay would be located in the fuse box under the hood of your Acura, though you will want to verify that with your local Acura dealer. I was unable to find the specific location of this relay as not all relay locations were identified in the online owner's manual.

The only other thing to keep in mind when installing is that you will need to insert fuses into locations 2 and 11 in the rear compartment that you referenced (like in the accompanying cut out of the installation manual I added).

This is a fairly straightforward installation that I am confident you would be able to do so I have added a link to a couple install videos as well as the instruction manual for you to check out.

expert reply by: Kyle S