I've wired a few Camrys for trailers.
First it's not necessary to wire it in before or after the light failure sensor. If you use trailers that use the 4 prong plug that has Ground, Tail, Right stop/turn and Left stop/turn Reese makes a module that converts the separate turn and brake lines to combined lines.
A wiring "dongle" can be made from a donor Camry by cutting out the harness plugs that are used in the trunk of a wrecking yard Camry. That way you don't run the risk of permanent damage to the harness of your car. The end result is also cleaner and more professional.
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90 Lexus ES250 Auto, 90 Lexus ES250 Stick, 88 Camry LE AllTrac Stick, 88 Camry Wagon

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