T420 Bluetooth location

[Artemis]

I recently got handed down a T420 (model 42369U3) but the bluetooth does not work. Could not find it in the Device manager. So I guess I would need to put in one.

So couple of questions:
1. Where exactly is the bluetooth card supposed to be on this machine? Tried searching online, but could not get a clear answer.
2. On the back side when I opened the RAM panel, I see an empty slot to the left of the RAM. Would that be the BT slot and if not what is it for?

Thanks

[TPFanatic]

The Bluetooth module lives on the underside of the palmrest, it plugs in to the same cable as the finger reader and touchpad. If your machine has a bluetooth icon between the WLAN and HDD lights on the display bezel, your machine should be equipped with the module.

My T420 had a strange glitch where the Bluetooth module is totally undetected by the laptop and OS, and apparently others have experienced this fault, and it even persists with replacement Bluetooth modules.

You can alternatively get Bluetooth integrated in a replacement modern WLAN card such as the Intel AC-7260 or AX210, among others from other manufacturers. A whitelist-removed modified-BIOS would be necessary for this.

[RealBlackStuff]

Get the T420 manual from the HMM link above.
Check Chapter 8, Section 1120.