[7'er-addict]

I hope you disconnected your battery whilst the DME was disconnected.

Otherwise, you may have burned your DME.

Although, it does sound like you may have a failing battery with the christmas lights you had prior to the work. Have it checked externally.

AFTER CHECKING THE BATTERY.. Find someone with a powerful diagnostic tool, ie an Autel. Have them check what is not communicating, and there lay your issue. Try clearing codes, and see what is still not communicating.

Hopefully you have a check engine light with key on ignition off. First press of the start button without foot on brake. You should also still have a check engine light when cranking, and after the car cycles the starter 15-20 seconds or so. If you don't have a check engine light, there is no communication with the DME.