If you don't use Bluetooth at all, you can disable it in BIOS. If you use it from time to time you can right click the Bluetooth Icon in the taskbar (assuming you're using Dell's software) and just click disable bluetooth radio.
However, Bluetooth doesn't use much power at all in a laptop in my experience. Bluetooth only is power hungry in cell phones where they batteries are tiny. You might get an extra 60 seconds of battery life with the Bluetooth card disabled.
The D430 is still fairly new, you should still be under warranty and be able to get the motherboard replaced (which includes the new switch.)