Radio works fine but the display is totally blank.

Radio with display often have a wire that powers the display. This is separate from what powers the unit, memory funcion, and from switched power that signals the device to power on. Each of those wires should receive power or signal from separate sources, respectively.
Inspect All connections. This includes wiring and contacts/terminals. If terminals are corroded, a small Allen wrench can be used to "de-pin" the plug for repair. The locking tab on each de-pinned terminal must be bent back to its original position, or it will fail to engage the plug, when pressed back into position.
It could be a faulty unit, though I encourage you to read the installation manual, if available, and eliminate the obvious while taking notes for future reference during the troubleshooting process. Good luxk