Right rear vertical yellow light random sometimes flashing. Parked in garage. No time-of-day or temperature relationship found. Don't know if happens while driving. Water intrusion? Worn wiring spot grounding? Or??? Any thoughts

 

Without so much as a clue to what your vehicle is other than maybe a CR-V, your issue is most likely a faulty BCM.

 

Sorry 2018 CR-V. Light does function normally on demand. Just these erratic flashes while parked. Not even the entire light, just lower part or one vertical line. Excure the ignorance, what is BCM?

 

Well we got one tooth extracted so I put it in the c’puter as a 2018 EX-L 2WD made in E. Liberty Ohio.

This should get you going on what it is, where it is and how big of a hole it will leave in your wallet:
https://www.hondapartsnow.com/genuin...20CVT&filter=()

Here is an AI splainin that is generally accurate:

In a 2018 CR-V, the BCM (Body Control Module) primarily controls functions related to the vehicle's body, including power windows, power mirrors, central locking, and interior lights. It also manages the vehicle's security features like the immobilizer system and keyless entry. Additionally, the BCM can interface with ADAS systems for features like lane keeping and adaptive cruise control.

Here's a more detailed breakdown:

• Convenience Features:
  The BCM handles the operation of power windows, power mirrors, and central locking systems, making it a key component for vehicle comfort and convenience.
• Security Features:
  The BCM plays a crucial role in vehicle security, managing features like the immobilizer system and keyless entry, preventing unauthorized access and theft.
• Lighting Control:
  The BCM controls the vehicle's exterior and interior lighting systems, including headlights, taillights, turn signals, and dome lights, adjusting brightness and turning them on or off based on ambient light sensors.
• ADAS Interfaces:
  The BCM can also interact with ADAS systems, providing input for functions like lane keeping assist and adaptive cruise control, enhancing the vehicle's safety and driving experience.

My suggestion is that you reset (carefully) the connectors on the bcm before you break out a parts canon.

Additionally, A good bi-directional scan-tool with Honda software may isolate the problem for you. The cheapest one I would try is the BlueDriver Pro.

Happy Hunting