Checking Ground-Providing Circuits

The best method of checking ground circuits is to measure the circuit voltage drop during component operation (or attempted operation).

• An ohmmeter may be accurately used if the battery has been disconnected. 
  • Expect less than 2 ohms for most small diameter (18 gauge and smaller) wires.
  • Disconnecting the battery is critical because DMM ohmmeter readings are commonly corrupted by the normal voltage present (battery connected) across body and chassis ground circuits.