Learned the hard way! This switch is self aligning when first locked into position - do not press the plunger or it will slide inside the switch.and may not then be long enough. This is normal but Haynes manual dosn't mention this. The fault on my Berlingo was that I didn't need to put my foot on the brake pedal to start the engine. It didn't affect starting but a gearbox warning message appeared on the display and the ECU light came on. All down to the brake light switch. A second problem was the brake lights were on all the time even though when tested the switch when removed from the mounting did operate the brake lights.