Have you tried this driver at Dell support?
I replaced the default wifi card with Intel ac 7260 dual band wifi + Bluetooth on my inspiron 660s desktop. the WiFi works great, 5ghz radio gets me 10 times the speed of what i got with older card. but Bluetooth shows up as unknown device with “USB” type in device manager and I am not able to find the driver.   any idea as to why windows is unable to find driver by itself, and where can i manually find?
Bluetooth driver for Intel dual band wifi AC 7260 in dell inspiron 660s