How can i start 307 that has a faulty multifunction switch?

To start a Peugeot 307 with a faulty multifunction switch, you can bypass the switch temporarily. First, locate the wiring harness connected to the multifunction switch, then use a jumper wire to connect the appropriate terminals that control the ignition. Ensure safety by disconnecting the battery before making any connections. However, this is a temporary solution; it's advisable to replace the faulty switch for a permanent fix.