How to Perform Porsche 924 Ignition Switch and Wiring Test

The following provides information about How to Perform Porsche 924 Ignition Switch and Wiring Test in order to determine the condition of the cranking portion of the ignition switch and the wiring from the ignition switch to the starter. You will need wire jumpers and multimeter to do this by yourself.

Procedures of Porsche 924 Ignition Switch and Wiring Test are described as follows:
1.   Ensure that you have disconnected the battery positive lead.
2.   Disconnect the electrical plug from the ignition switch
3.   Connect an ohmmeter between Terminals 30 (to the red wire) and 50 (to the red wire with black stripe) on the ignition switch
4.   Turn the ignition switch to the start position as if cranking the engine and read the resistance
5.   When the switch is turned, the resistance should go from and infinite resistance to approximately 0 ohms
6.   The ignition switch is bad and should be replaced, if the correct resistance is not obtained

And then check the ignition wiring if the ignition switch’s result is good. Here are the procedures:
1.   Disconnect the wire from the switch terminal on the starter solenoid
2.   Make up a jumper to reach from the starter to the ignition switch
3.   Attach the jumper from the switch lead at the starter solenoid to the terminal on the ignition switch electrical connector
4.   With an ohmmeter then check the wire resistance, it should be 0-5 ohms approximately. It is broken and should be replaced if not showing that resistance value

source: clarks-garage.com