Blind spot detection - intermittent

[22Brad]

Help! My late model outback with blind spot detection fails to indicate a car next to me - sometimes.

Subaru can find nothing wrong. I had car calibrated using my dealer and results were perfect no faults with sensors on front or back of car. Could not duplicate. Indicator lights on mirrors worked normally. No car faults were noted in the I pad diagnosis.

My drive home from the dealer the (Right side only) Mirror light did not illuminate for any vehicle I passed or that passed me on the right side of car. This is intermittent about 50 percent of the time. Situation on a long drive of several hours had No light for periods of an hour or so then normal operation resumed for the next hour or so. To make it even more unusual I will say that at times the blind spot will work for Cars only and shockingly not see a massive semi truck.

Something unusual in my cars systems or computer software??

Car has never been bumped or hit.

 

[Hjulbyhavn]

My computer experience suggest a wire harness/connector problem. The trucks must be Russian spy's or secret service agents or something ;-)

 

[WDM]

Everyone needs to pay attention to the passenger side blind spot indicator. This is something you don't notice unless you are going to change lanes to the right. I also have an intermittent problem with the right side only like 22Brad mentioned. I have a 23 Forester Touring. I told my dealer about it so he checked it out... no problem detected, couldn't duplicate. So I videoed the mirror while I was driving down the interstate for my dealer. I could pass cars on my right and it would intermittently not detect cars. It would pick up 10 in a row and then miss 2 and pick up one and then miss 6 in a row. I took it back to the dealer. They gave me a loaner 2024 Outback while they checked out my Forester. The 2024 Outback had the same problem with its blind spot detection. The dealer says they replaced both radar units and sensors on my Forester, but I still have the same problem. Made sure they noted it and have it in my service record in case there is ever a re-call when someone figures out what the problem really is. My wife has a 2025 Outback that does the same thing. I'll bet there are a lot of Subarus that have the same problem but unless you are watching it as you pass a car you will never notice it. Start paying attention as you pass cars and I'll bet your Sabaru has the same problem.