Toyota 4Runner

Disconnect the solenoid connector. Using an ohmmeter, measure resistance between terminal No. 3 and 4. See Fig 1. Resistance should be 12.5-16.5 ohms. If resistance value is not as specified, replace the solenoid. See KEY INTERLOCK SOLENOID under REMOVAL & INSTALLATION.
Disconnect solenoid connector. Momentarily supply battery voltage to terminal No. 4 and ground terminal 3. See Fig 2. Ensure an operating sound is heard. If the solenoid does not operate, replace the solenoid. See KEY INTERLOCK SOLENOID under REMOVAL & INSTALLATION.

Fig 1: Measuring Resistance At Key Interlock Solenoid (Toyota 4Runner)

Fig 2: Testing Operation Of Key Interlock Solenoid (Toyota 4Runner)