If turning the ignition switch does not cause the starter to run, follow these steps:
- Turn of ignition, put gearshift in neutral, pull up hand brake.
- Open bonnet and locate starter relay.
- On the started relay jumper the brown wire on terminal C1 to the white/brown wire on terminal C2, the starter should run. If not, you have a bad solenoid, or bad connection from relay down to the solenoid coil. If you hear the starter solenoid click then you could have a bad starter.
If it runs, then with ignition off, jumper brown wire on relay terminal C1 to the white/red wire on the relay terminal W1.
If the starter still doesn't run, then you have a bad starter relay. If it does run then I would suspect the ignition switch start contact, unless your car has a seatbelt sequential control system that is preventing the starter relay from activating.