Error with Minolta 800si battery grip

My battery grip developed an error, after one frame it reads the film at being at the end of the roll and rewinds. Same error on 2 different bodies. Other than a short likley a bad chip. I will open it up latter this weekend to look for a lose wire or the like. Well maybe the film sensor is stuck, not sure how the sensor works.

The battery grip only provides power to the camera and allows you to fire the shutter , change aperture and shutter speeds and AEL button .
Anything to do with film transport is controlled by the camera .

How does the camera behave without the grip on ?