Creda T622 CW?

How do I fix / No heat
Power reaching thermostats and heating element until I push the start button. Machine starts no problems and drum spins but no heat emitted. I've noticed that power stops reaching the element and thermostats once on. Open front door and close it again power is back flowing through to element and thermostats. I have replaced both the heating element and the thermostats ( Green dot ) I believe that it might be linked to the microswitch leveler, which is sistuated under the wheel drive housing. It might also be linked to the front door thermostat ( Silver ) which is sitiuated just inside door, drum, under the rubber seal at top right. Will replace these two units and see it works .......... any ideas most welcome...