How Does Hopkins Trailer Wiring Install on 2010 Volvo V70

Updated 10/01/2025 | Published 09/30/2025

Products Featured in This Question

Hopkins Plug-In Simple Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(31)

$71.51

Hook Probe Circuit Tester

(60)

$12.27

Question:

I want to install a trailer hitch and wiring on my 2010 Volvo V70. I am trying to understand the wiring connection process before I order the hitch and harness. Two people have mentioned that their Volvo XC70s lower brake lights only work with the hatch open. When the hatch is closed, only the upper brake lights work. This is exactly what my V70 does. Anthony R commented about this issue on 9/18/2019 and the answer was to plug the harness into the upper light. This is not possible as the upper lights are in the hatch and there is no plug. The only accessible plug is for the lower lights and that brake light will not work with the hatch closed. Steven reported this issue on 4/13/2025. He was going to buy a Curt harness because it had a wire to go to the hatch light. I have seen no other mention of running a wire to the hatch light. There were no response to Steven. Even with the Curt harness, if one connects the brake light wire to the lower brake light, it will not work with the hatch closed. The only brake light which works all the time is the third light on top of the hatch and I have seen no mention of connecting to that. Is that the hatch light that Steven mentions? If it seems like I am confused, I am. I like the idea of the plug and play features of the Hopkins harness, but I need to be sure how to make it work. If someone can explain how to connect the harness to my car, I will place an order. Thank you for reading all this. Alan

asked by: Alan

Expert Reply:

Hey Alan, I totally understand your frustration and confusion over how the Hopkins kit part # HM11143735 installs on your 2010 Volvo V70. This kit fits a few vehicles so the brake light situation you mentioned is an oversight on their part. So what you would have to do with this kit is find the stoplight circuit for that red wire. To find that you will need to look at the top of the door hatch threshold and look for the wire loom bundle that basically carries all of the light circuits that are in the hatch.

There will be a few wires there but with a circuit tester like the part # PTW2993 you could probe them all and find the one that has power when the brakes are applied only. You'll then want to note that wire color and then track it down behind the panels in the vehicle interior to use it for the red wire of the Hopkins kit. I know this is a lot more involved than just plugging in a few connectors so I understand if that's more than you were wanting to do.

expert reply by: Jameson C

Alan

10/1/2025

Thanks for your reply. My understanding now is that I need to find the power for the third brake light in the top of the hatch. I splice that to the red cable which is part of the left hand tail light connector. I assume I cut the red wire so I am not feeding the lower brake light. This makes sense to me. Is this correct?