Today I installed a towing cable harness in my 2006 Toyota Highlander Hybrid and I had a bit of difficulty at first because the correct connector was somewhat hidden (wrapped up in protective material) and the connector I found first was a near fit - I could put the two parts together with some force (enough that it felt wrong) - but the actual plug and sockets of the connections were definitely wrong.

I eventually found the right connector but only after finding an additional connector that was no where near the right fit.

What is the best way to determine what the intended use of these extra connectors is?

  • 1
    What does the owner's manual say about it?
    – Nick C
    May 31, 2018 at 15:18
  • Can you provide a picture of the connector with the wiring exposed for an ID?
    – Ben
    May 31, 2018 at 19:48
  • Without more data it's hard to be helpful, but it should be a bus for brake controllers or other accessory systems. Read your harness just for lights or did it also include brakes? This diagram may help. For an RV there are more poles needed, so maybe that. May 31, 2018 at 23:20
  • @kyle_engineer thanks but i wasn't asking about the wiring for the trailer. Jun 1, 2018 at 12:35

1 Answer 1


You will need the workshop manual AND the correct wiring diagram for the car to be able to ascertain the connectors and their respective functions...

  • So basically ask the dealer? :) May 31, 2018 at 17:25
  • Depends on the dealer... the ones I dealt with were always helpful to me... But that was probably because I was not a “normal” customer and I had solved problems for them in the past...
    – Solar Mike
    May 31, 2018 at 17:40

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