Meghan --

The voltage regulator controls and stabilizes the voltage for the temperature and fuel gauges so their readings don't vary as the car's voltage goes up and down slightly.

It's a small black square transistor-like device, perhaps 1/2"x1/2" by 1/8" thick, has three leads on one end and a metal "fin" (heat sink) on the other end.

The compensating board is a printed circuit board about 3" long by 1" wide and is mounted inside the dash cluster. When the cluster is pulled, the large circuit board must be removed from the plastic housing to reveal this plug-in circuit.

The compensating board modifies the temperature reading to keep the needle centered on the gauge across the engine's normal temperature variations -- but will quickly show a high reading when the temperature exceeds about 240 degrees.

The compensating board simply plugs into the main cluster board, and is physically held in by two plastic clips.

Sometimes the board develops a bad solder connection, and can be refurbished simply by resoldering. More often, one of the small pins that connects the compensating board to the main board becomes tarnished and interfers with voltage or signal levels. Cleaning and tightening will often solve this problem. But if you're paying a mechanic, then installing a new board is probably wise.