Electrical Circuit Inspection Procedure

Check Open Circuit

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
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Continuity Check Method
NOTE: When measuring the resistance, lightly shake the wire harness up and down or from side to side.

Specification (Resistance)

1Ω or less → Normal Circuit

1MΩ or Higher → Open Circuit
1. Disconnect connectors (A), (C) and measure resistance between connector (A) and (C) as shown in [Fig 2].
  If the measured resistance of line 1 and 2 is higher than 1M Ω and 1 Ω, respectively in [Fig 2], the line 1 is the open circuit (line 2 is normal). To find the exact break point, inspect the sub line of line 1 (the next step).
  
  Fig 2: Measuring Resistance Between Connector (A) And (C)
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2. Disconnect connector (B), and measure resistance between connector (C) and (B1) and between (B2) and (A) as shown in [Fig 3].
  If the measured resistance between connector (C) and (B1) is 1M Ω or higher, and the resistance between (B2) and (A) is 1 Ω or lower, line 1 of connector (C) and line 1 of connector (B1) are open circuits.
  
  Fig 3: Measuring Resistance Between Connector (C) And (B1)
  Courtesy of HYUNDAI MOTOR AMERICA
Voltage Check Method
1. With each connector still connected, measure the voltage between the chassis ground and terminal 1 of each connectors (A), (B) and (C) as shown in [Fig 4].
  The measured voltage of each connector is 5V, 5V and 0V respectively. So the open circuit is between connector (C) and (B).
  
  Fig 4: Measuring Voltage Between Chassis Ground And Terminal 1 Of Each Connectors
  Courtesy of HYUNDAI MOTOR AMERICA

• Check Short Circuit

Test Method for Short to Ground Circuit
- Continuity Check with Chassis Ground
If short to ground circuit occurs as shown in [Fig 5], the broken point can be found by performing Step 2 (Continuity Check Method with Chassis Ground) as shown below.

Fig 5: Checking Short Circuit
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Continuity Check Method (with Chassis Ground)
NOTE: Lightly shake the wire harness up and down, or from side to side when measuring the resistance.

Specification (Resistance)

1Ω or less → Short to Ground Circuit

1MΩ or Higher → Normal Circuit

Disconnect connectors (A), (C) and measure resistance between connector (A) and Chassis Ground as shown in [Fig 6].
The measured resistance of line 1 and 2 in this example is below 1 Ω and higher than 1MΩ respectively. Specifically the short to ground circuit is line 1 (Line 2 is normal). To find exact broken point, check the sub line of line 1 as described in the following step.

Fig 6: Measuring Resistance Between Connector (A) And Chassis Ground
Courtesy of HYUNDAI MOTOR AMERICA
Disconnect connector (B), and measure the resistance between connector (A) and chassis ground, and between (B1) and chassis ground as shown in [Fig 7].
The measured resistance between connector (B1) and chassis ground is 1Ω or less. The short to ground circuit is between terminal 1 of connector (C) and terminal 1 of connector (B1).

Fig 7: Measuring Resistance Between Connector (B1) And Chassis Ground
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• Testing For Voltage Drop

This test checks for voltage drop along a wire, or through a connection or switch.
1. Connect the positive lead of a voltmeter to the end of the wire (or to the side of the connector or switch) closest to the battery.
2. Connect the negative lead to the other end of the wire. (or the other side of the connector or switch)
3. Operate the circuit.
4. The voltmeter will show the difference in voltage between the two points. A difference, or drop of more than 0.1 volts (50mV in 5V circuits), may indicate a problem. Check the circuit for any dirt and loose connections.
Fig 8: Connecting Negative Lead To Other End Of Wire
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