2016 Toyota Highlander Trailer Wiring | etrailer Fastest shipping available and a lowest price 2016 Toyota Highlander trailer wiring guarantee. Expert lifetime technical support on all purchases. Complete 2016 Toyota Highlander Trailer Wiring installation instructions and customer reviews. Call 800-298 Toyota repair manual free download | Car Manuals Club Toyota service, workshop, owner’s and repair manual; electrical wiring diagrams, fault codes/ diagnostic trouble codes in PDF – free download more than 200+ Toyota manuals!. Toyota repair manuals, owners manual & electrical wiring diagrams Toyota Highlander Stereo Wiring Diagram - the12volt Toyota Highlander Stereo Wiring Diagram. I would recommend not using the factory amp and wiring your head unit directly to the speakers. To remove the head unit, first remove the trim bezel which is held on with 8 clips. Next remove the 6 bolts that hold the A/C and radio assy in. There are four bolts on each side of the assy. that hold the radio onto the bracket.