Mine don’t work either and as they are all dealer fit, guess 15 years on they had their life expectancy.
I have another set to go in, just working out if I can pull the new wiring through, taping it to the old wiring.
Failing that it’s bumper off ☹️
if Lexus used the same company it will be a Scorpion SPS9040 Sensor kit, did take the unit apart but no moisture or corrosion inside .
Unit can be found behind the grey trim o/s rear of boot 👍🏻