Testing For Proper Ground

Using a volt/ohmmeter, check for continuity between breakout box pin No. 25 and ground and between breakout box pin No. 27 and ground. If there is no continuity between either pair of Test points, system is functioning properly. Repeat service code Test and verity that there is still a service code displayed.
If there is continuity, a short is indicated. If a short is indicated, check fluid level sensor connector pin No. 1. Disconnect fluid level sensor connector. Check for continuity between fluid level sensor connector pin No. 1 and vehicle ground.
If continuity is present, repair or replace circuit No. 512. If no continuity is present, check fluid level sensor connector pin No. 2. Test for continuity between fluid level sensor connector pin No. 2 and ground. If continuity is present, replace pressure warning switch and the pump motor relay. If no continuity is present, check pressure warning switch.
Disconnect pressure warning switch 5-pin connector. Check for continuity between pressure warning switch connector pin No. 3 (sensor side) and ground and also between pin No. 5 (sensor side) and ground. If there is continuity, replace pressure warning switch and the pump motor relay. If no continuity is present, check pressure warning switch pin No. 5 (harness side).
With pressure warning switch connector disconnected, check for continuity between connector pin No. 5 (harness side) and vehicle ground. If continuity is present, repair or replace circuit No. 535. If no continuity is present, reconnect all connectors, Test drive vehicle at a speed above 25 MPH to clear codes.
Restart self-Test diagnosis and verify any service codes. If no codes display, system fault has been repaired. If service codes display, diagnose lowest codes first following appropriate self-Test procedure.

NOTE: The following charts A through J are for use with Breakout Box on all Ford Motor Co. models with ABS.