Stoplight Switch Circuit
- Turn ignition off. Check stoplight fuse. If fuse is blown, replace fuse and check operation of stoplight switch circuit. If operation is not normal, check for short between terminal No. 16 of computer and terminal No. 1 of stoplight switch and fuse. See Fig 1.
- Disconnect stoplight switch connector, check for continuity between terminal No. 3 (terminal No. 2 on Corolla, MR2 and Supra) of connector and body ground. If no continuity is present, check for open between terminal No. 3 and body ground. Test body ground circuit.
- If continuity is present, check stoplight switch operation. If stoplight switch is not operating properly, replace switch. If switch is operating properly, reconnect stoplight switch connector.
- Disconnect computer connector, check for battery voltage between terminal No. 16 and body ground with brake pedal released. If no battery voltage is present, check for open between terminal No. 16 of computer and stoplight fuse.
- If battery voltage is present, check for battery voltage between terminal No. 15 and ground with brake pedal depressed. If no battery voltage is present, check for open between terminal No. 3 (terminal No. 2 on Corolla, MR2 and Supra) of stoplight switch. If battery voltage is present, replace cruise control computer.