How would you diagnose a short to supply vs a short to ground in a sensor circuit using a multimeter?

Prepare for the OCC SACA Sensor Logic Systems 1 (C-205) Exam. Study with detailed questions and insightful explanations. Get ready for your certification!

When you’re using a multimeter to diagnose a sensor circuit, you’re looking at how the input node routes to the two rails: the supply and ground. With the circuit unpowered, a short to the supply rail will make the input effectively connected to V+, so resistance between the input and the supply reads near zero. A short to ground, on the other hand, ties the input to ground, so resistance between the input and ground reads near zero. The key is to compare these two paths and confirm which rail is shorted.

To be sure you’re identifying the fault correctly, isolate the sensor or disconnect the input so you’re measuring a single path without other components creating alternate routes, then check continuity. If you see a near-zero reading between input and supply, that points to a short to supply; if you see near-zero between input and ground, that points to a short to ground. If both readings stay high, the fault isn’t a direct short on those paths, or you may need to further isolate to rule out other paths.