I received the clip in extension, put it in, and didn't see a change in things. I think you are right, at least in my thought pattern, that the weight sensor is still in play here. My understanding of the goal of that sensor is to tell the airbag system whether there is or is not someone in that seat. That tells the system whether or not to allow the deployment of the airbag. It is there for economic reasons, I believe. So in an accident, if no one is in the passenger seat, don't deploy the passenger airbag. Something I will need to check is if you can manually turn off the airbag to the passenger seat, I believe with your key (child seat safety override or whatever), then clip in the extension, will that get rid of the light? I have other issues to fix still. I need to sort out the second row airbag bypass, since I took that row out too. So I will have a light in the dash regardless, until I get it all sorted out. Sorry I am not more help here.
Cheers,