You have added a SIM card in the slot; you know you have it the right way up, and you have tried a different SIM card, just to be sure.
SIM empty
You keep getting the message that the SIM slot: SIM empty.
SIM Card
Some models for the branded Android headunits can add a SIM card for Data. You don’t need to hotspot your phone for an internet connection, but you need a second SIM plan to get the additional SIM card.
No Hot Spot
Not having to hotspot your phone or not even having to bring your phone with you can be a great advantage. Maybe you use a locked-down works phone or don’t want to set up hot spotting each time. Having the facility for a dedicated SIM card in your Android headunit can be a huge plus.
SIM Empty
But what happens if the Android headunit does not recognize the SIM card? There is a warning message that SIM Slot: SIM empty, No SIM detected, or something similar that indicates the SIM card is not working in the head unit.
You’ve already tried a different SIM card.
You know it works because you tried the new SIM card on the phone.
Solution
Try inserting the SIM card in the slot and power down the head unit. Switch it off and disconnect the car battery. When you reconnect the car battery, it will force a cold boot of the Android headunit. It may take longer to cold boot. During this cold boot (long bootup), the Android headunit checks for the SIM card presence and initializes it. When the unit has fully rebooted from cold, look now for the SIM card SIM slot presence.
You should now have a SIM card active in the SIM slot, and data should be active.
