J1 Check Brake Lamp Switch

NOTE: Do not apply brake pedal while performing this test.

- Connect Rotunda 60-pin Breakout Box 014-00322 with Rotunda Anti-Lock Brake Adapter 007-00116 or equivalent to the anti-lock brake wiring harness connector.

- Turn the ignition switch to the RUN position.

- Measure voltage between breakout box pins 20 and 13.

- Is B+ present?

YES -- Replace stoplight switch or service circuit 511 (LG). Restore vehicle. Retest system.

NO -- Go to J2. J2 Check Traction Assist Valve