How To Check Battery Connection In Car. If possible check the age of the battery by inspecting the battery date code. If your multimeter is not autoranging set it to 20V DC.
Another symptom of a bad or failing cable is the presence of corrosion on the terminals. With the battery connected the dome light should come on when you open the drivers side door. Corrosion develops as a result of the acidic vapor produced by the battery when it becomes hot from exposure to the heat of engine operation.
A normal car battery voltage reading is 126V when the vehicle is off.
Over time the vapor can begin to corrode the terminal and cause corrosion to. The poor connection to your battery terminals could be because of corrosion making your car lights dimmer or flicker when driving. The vice versa is the wrong connection. If your multimeter is not autoranging set it to 20V DC.
