1993 Nissan Sentra 93 Sentra Runs Fine, but no Electrical

93 Nissan Sentra, 1.6 with 83k miles. I start it up this morning and as the shoulder harness is coming back, all interior electrical goes out, but the car is running fine. Headlights work, and the backlight of the dash clock works, but no time is displayed. No radio, brake or dome lights, spedometer, trunk light, cig lighter. I checked all the under dash fuses and all are in good shape and never did smell anything burning. Recently a new alternator and battery were installed, however, it has been driven several days since then with no ill effects.
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Thoughts on where I should start?

Thank you