“Blind spot monitor not available” help

When yours stopped working, did it give you the error?

 

You can check the associated relays indicated in these schematics. However because you are getting that error message, I would think that is coming from the CAN network on the sensor module itself. Possibly a self check, does it come on with igntion?

What is your current system voltage?
check battery, then engine running, post numbers.

I'm not too familar with blindspot stuff, but these look like the radar types (as opposed to ultrasonic, which you can hear them clicking to know if they are working, but those are mostly for backing up). I believe blindspot are Ka band radar, i know they are on some other cars, you could try to get someone with a radar detector to check them. I know they trigger a lot of false radar readings. are you getting any of the warnings in the side mirrors? Left and Right both inoperable?

 

Those sensors are pretty well protected from stuff getting flung in there, but a lot of stuff does accumulate in that area if you've been through a bit of mud. I think there's a special calibration procedure, so if you've bumped something with the bumper corner, that might have thrown things out of whack. I don't know what kind of startup self-checks the system would do to validate operation, but this sounds like an electronic issue where a sensor is failing the initial check. You've got to figure out why it says it is unavailable, which to me sounds like some kind of electronic failure. How old is the battery? Those sensors are about the farthest sensitive thing from the battery, so wondering if a slight low voltage to them would cause a self-check failure. Mine have been removed, and the wires to those sensors are really thin. Maybe hook up some jumper cables to another battery and run through the startup procedure again.

 

I’ll have to call and double check

 

That used to happen to me. I’d just turn them off and they’d work fine after I stopped and restarted the truck. Never cared enough to figure out why. Weren’t dirty either.

 

Pretty common issue with ice and sometimes rain with my system after it has been sitting overnight. Usually clears up after driving a bit. It is just the sensors reporting no line of sight.

 

My BSM goes out like this a few times a year. I turn it off -- wait a few days, turn it back on and it eventually works. Lather, rinse repeat.
btw I live where there is no rain or snow, so that is not the issue.