The home / car check mechanism relies on "that springy electrical contact thingy" in the power jack "opening" and "closing" with the power plug insertion, right (excuse crap English )

- Are you sure the one you fitted supports that feature ??

- Is your power adapter plug the right size for the jack, if it's not the right diameter (ie: too small) it will give the intermittent behaviour you're seeing ??

.... just a couple of thoughts, hope you sort it - cheers, Sim