* Faulty voltage regulator. The voltage regulator is responsible for controlling the amount of voltage that is sent to the electrical components in your car. If the voltage regulator is faulty, it can cause the voltage to fluctuate, which can in turn cause the gauges to bounce up and down.
* Bad ground connection. A bad ground connection can also cause the gauges to bounce up and down. The ground connection is responsible for providing a path for the electrical current to flow back to the battery. If the ground connection is bad, the current can't flow properly and it can cause the gauges to bounce up and down.
* Faulty turn signal switch. The turn signal switch is responsible for turning on the turn signals. If the turn signal switch is faulty, it can cause the gauges to bounce up and down when you turn on the signal.
To diagnose the problem, you will need to check the voltage regulator, the ground connection, and the turn signal switch. If you are not comfortable doing this yourself, you can take your car to a mechanic for diagnosis and repair.
