Vacuum Fluorescent (VF) Dimming

WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

The vacuum florescent lamps will be at full brightness when the ignition is on and the park lamps are off. When the park lamps are turned on, voltage is supplied by the instrument panel lamp fuse supply voltage circuit to the VF display components. The VF display will then dim to the level set by the dimmer switch. The brightness of all the vacuum florescent displays is determined by a variable voltage signal produced by the dimmer switch and sent through the instrument panel lamp supply voltage 1 circuit. With the park lamps activated, the following components will dim for night time viewing:

The VF display of the radio
The HVAC module
The Instrument Cluster VF displays

When the instrument panel lamp fuse supply voltage is present, the VF display is at its high brightness for daytime viewing. When the park lamps are on, the VF displays receive two signals. The first from the instrument panel lamp fuse supply voltage circuit and the second from the instrument panel lamp supply voltage 1 circuit.