1986 Cadillac EL Dorado Electrical

Electrical problem
1986 Cadillac El Dorado Engine Size unknown Front Wheel Drive Automatic 70000 miles

Dash lights began diming and then then coming back. Continued to get worse until no lights at all.
Replaced cluster with used cluster obtained on internet. It is doing the same thing as the previous one. Lights are diming and then coming back. Could it be something else?