For what it's worth

Here - for my reference as much as anyone else's - is a photo of how the connections look on the back of the timer panel on a Panasonic Microwave (my model, anyway). Note the two two-pin connector plugs: the red one goes on the inside (nearer the oven area) and the white one on the outside (nearer the outer casing). If you get them wrong, then the grill comes on when you should be microwaving (and presumably vice versa).

To remove the timer panel (I had to do this because the door release got stuck: broken plastic post), first remove the power plug - there are dangerous voltages inside a microwave. Now go and do something else for a while - voltages can be stored even after disconnection - see this useful article

Now, remove the two screws close to each other at the top, release the two white plastic tabs on the vertical edge, then pull out and upwards to release the two white plastic tabs at the bottom.