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Sometimes, going back to the basics can make the difference between a quality repair and a failed repair. Electrical circuits are nothing new in the collision industry. Vehicle circuits primarily use 12 V direct current (DC) for electricity, which requires every circuit to have a good ground in order to be closed. The more advanced vehicle electrical systems become, the more need there is for additional grounds.
If a vehicle only had one ground, it would make for easy diagnosis when having an electrical failure after a collision repair. With only one location, if the ground was disconnected, nothing electrical would work on the vehicle. With modern vehicles using multiple grounds, electrical problems can become more difficult to track down. Different joining methods and sound deadening are also part of why multiple grounds may be needed. Adhesives and seam sealers act as insulators, not allowing electricity to flow through the entire vehicle chassis, the same as metal on metal.
If a ground is not making good contact (a common reason is painting over the ground location) or not connected, it does not mean it always disables everything on that circuit. It may cause circuits to become underpowered or function intermittently.
Electrical ground failures also tend to affect multiple unrelated systems, which can lead to a misdiagnosis. Electrical components are not always completely de-energized by a bad ground, but they may get lower current flow due to the distance from the ground and the resistance from seam sealers, adhesives, etc.
If there is a ground issue, changing out parts does not fix the problem. In order to prevent creating a bad ground, attention to detail is required. Diagnosing a bad ground requires a proper electrical diagnosis process using diagnostic flow charts and/or wiring diagrams to fix the problem.
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Article validated in 2025