Chosen Solution
Hello all, I have an iPhone 6s, it does register that there is a SIM card but says no service. Bluetooth and WiFi are working fine. I replaced the rectangle cellular antenna found in the top left of the phone, and no difference. I also replaced the charging dock and again no difference. Tried searching for networks, however nothing appears. Does anyone have any ideas? Thanks for your advice!
After your repair attempts I’d be inclined to think of a baseband issue, maybe the IC itself or a related component. Try dialing *#06#, you should be getting the Imei code in return..if you don’t, a Bb problem would be confirmed>
The SIM is probably fried.
