Electrical Circuit Inspection Procedure

Open Circuit Test

1. Procedures for Open Circuit
   • Continuity Check
   • Voltage Check

   If an open circuit occurs (as seen in Fig 1), it can be found by performing Step 2 (Continuity Check Method) or Step  3 (Voltage Check Method) as shown below.

   Fig 1: Checking Open Circuit

   Courtesy of KIA MOTORS AMERICA, INC.
2. Continuity Check Method
   NOTE: When measuring the resistance, lightly shake the wire harness vertically or horizontally.

   Specification (Resistance) 

   1Ω or less → Normal Circuit

   1MΩ or Higher → Open Circuit

   1. Disconnect connectors (A) and (C), and measure resistance between connectors (A) and (C) as shown in Fig 2.

      In Fig 2, if the measured resistances in lines 1 and 2 are "over 1 MΩ" and "below 1 Ω" respectively, line 1 has an open circuit. (Line 2 is normal.) To find the exact broken point, check the sub line of line 1 as described in the next step.

      Fig 2: Measuring Resistance Between Connectors (A) And (C)

      Courtesy of KIA MOTORS AMERICA, INC.
   2. Disconnect connector (B), and measure the resistances between connectors (C) and (B1), and between (B2) and (A) as shown in Fig 3.

      In this case, the measured resistance between connectors (C) and (B1) is higher than 1 MΩ and the open circuit is between terminal 1 of connector (C) and terminal 1 of connector (B1).

      Fig 3: Measuring Resistances Between Connectors (C) And (B1)

      Courtesy of KIA MOTORS AMERICA, INC.
3. Voltage Check Method
   1. With each connector still connected, measure the voltage between the chassis ground and terminal 1 of each of connectors (A), (B) and (C) as shown in Fig 4.

      The measured voltages of connectors are 5V, 5V and 0V respectively. So the open circuit is between connectors (C) and (B).

      Fig 4: Measuring Voltage Between Chassis Ground And Terminal 1 Of Each Of Connectors

      Courtesy of KIA MOTORS AMERICA, INC.