How To Use Circuit Tests

WARNING: This page is about a different car, the 1992 Mercury Tracer, 1992 Ford Probe, and 1992 Ford Escort. However, it is still accessible from the selected car via links, so may be relevant.

1) DO NOT perform any CIRCUIT TEST unless specifically instructed by a procedure under QUICK TEST or SWITCH MONITOR TEST. Ensure all non-EEC related faults are corrected. FOLLOW EACH TEST STEP, IN ORDER, UNTIL FAULT IS FOUND. When more than one code is received, start with the first code displayed.

2) CIRCUIT TESTS check electrical circuits to ensure they are okay before replacing sensors or any other components. Always test circuits for continuity between sensor and ECA. Test all circuits for short to power, opens or short to ground.

3) DO NOT connect any test light, or measure voltage or resistance at ECA unless specified in testing procedure. DO NOT pierce wiring. If backprobing is specified, always backprobe harness side of connector; DO NOT probe connector side.

4) Isolate both ends of circuit and turn ignition off whenever checking for shorts or continuity, unless specified otherwise. Disconnect solenoids and switches before checking circuit continuity or energizing solenoids.

NOTE: A short is defined as a resistance value of less than 5 ohms.