Battery cables, like most wires, are designed to operate within certain current and temperature ranges. Stepping outside those ranges can be dangerous and can possibly cause a fire.Indicators of possible temperature issues include hot wire, melted insulation and smoking connections. These conditions can be caused by a close heat source or excessive current flowing through the wires. When any of these conditions arise, the source of the problem must be found as soon as possible to avoid damaged equipment and ensure safety.
Look for high-temperature items near the ground cable, such as an exhaust pipe or exhaust manifold. Check for damaged or missing heat shields. Heat shields are designed to protect cables and other sensitive items from excessive heat.
Inspect all wire connection points for loose connections, which create a point of high resistance that can heat up to very high temperatures. These temperatures can melt insulation and connectors and start a fire.
Disconnect both battery cables. Connect the negative probe of the ohmmeter to the black battery cable and connect the positive probe of the ohmmeter to the car frame. Measure the resistance of this connection. It should be 0 ohms. If not, either the cable is bad or the ground wire to vehicle frame connection is bad.
Check the positive battery cable. Connect the positive probe to the positive battery cable and the negative probe to the car frame. This connection should have a high resistance. If it has a very low or zero resistance, then there is a short to ground on the positive side of the system.
