If the switch has a symbol that looks like a "tree", then it is the power antenna up and down switch. If the car had a factory fitted antenna then this switch is wired to the antenna via a black module box, which controls the power to the antenna. This box is fitted just above the left hand side kick panel, just inside the dash next to the left hand vent duct. If the module is working you will hear a faint click noise when you have accessories power on an you press the switch. For the antenna to work, it must be compatible with the module (if factory fitted) and is wired correctly via the switch and factory wiring loom. Sorry if I have given too much information.