Toyota Repair: 99 Camry right rear blinker, electrical experience, wire harness

Question
My right rear blinker won't work anymore. I've replaced bulbs, mechanic checked fuses, Toyota did diagnostic and said it's the integration relay, and will replace it for $600. Have read online that it could be after market bulbs that do not pick up the signal the same as a Toyota bulb. Is this correct? Do you think it's the integration relay? Should I just go ahead with this really expensive repair for the blinker? Is there any way for me to replace the integration relay myself to save on labor? Thanks for your help.

Answer
No, it's not the integration relay, it has nothing to do with the turn signals, it's more likely a wiring problem or a problem with the bulb sockets or a bad ground, there is also a relay that controls the rear lights, it's located inside the trunk on the left behind the carpeting, there have also been problems with the wiring in the wire harness that runs along the left trunk hinge, the wires inside the harness can break, the wires can be checked by cutting the insulation open and checking for open wires, these are some of the more common problems, a good technician with electrical experience should be able to give you a better diagnosis than the integration relay replacement.