2004 vehicle, its an intermittent code B1153, which indicates a seat position sensor.

I read throughout that it can be a harness or the sensor itself and a common issue in early GX470s, I just need to know the right part number for the harness and where best to get it.

 

Does the code point you to a driver's or passenger seat position sensor? I'm pretty sure this was the same problem I had when I purchased my GX, and it was fairly easy to repair.

Unbolt the seat and tip it back, trace the wiring harness from the seatbelt buckle and try and locate the broken wire in the harness. Extend the harness as part of the repair, so it doesn't happen again in the future.

 

The code does not differentiate between drivers and passengers side, no. Should be an updated harness but I don't know where everyone buys parts for Lexus, RockAuto didnt have the selection.

 

My understanding is that to replace the harness you need to dig deep into the dash to get to the one end, making it a big job. If you can repair the harness, it's the way to go for sure.