I'm posting this here in the hope of getting some insight before I have to take my car to the dealer. I dread the dealer because they are quite terrible and their idea of "fixing" something of throwing parts at it until the problem goes away. They are awful at diagnosing anything. So, I'll start at the beginning. 2017 Prius Prime with Tech. I noticed when I'd push in the brake to start the car the RH turn signal on the dash would illuminate. See image 1. After driving around (or sometimes immediately) the PCS and ICS malfunctions would pop up on the dash. Cruise control would not work also throwing an alarm. Images 2 and 3. I pulled out a variety of consumer-level OBD readers and most found no error. However, one found a Stoplight Relay Circuit error. Image 4 With this info, I had the wife push the brake pedal while I examined the tail lights. All tail lights and brake lights work. BUT!! The RH turn signal light would very gently illuminate. It's far less obvious than what the photo shows. It's lit..but very dim. Goes on/off with brake pedal. See image 5 Cliff Notes: left turn signal is illuminating when brakes are pushed causing various alarms to be thrown. Does anyone far more intelligent than I have any insight into this? Thanks!! SM-G981W ?
