How to remove built-in 3G/4G modem from Thinkpad T440s?
Solution 1:
From the T440S Hardware Maintenance Manual.
T440S HMM
The steps below give you the color codes for the wires
I think from your description that you should be OK
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1040 Wireless LAN card (correction to this post)
When installing:
Plug the gray cable into the connector labeled MAIN or 1 on the card
Plug the black cable into the connector labeled AUX or 2 on the card