1991 BMW 525 Electrical System Malfunction

Recently, the cars electrical system shut down. The central locking system, the windows, seat adjustments, interior lights and the radio quit operating. The A/C, driving lights & ignition remained operative.

Removing the electrical modules in the engine compartment & re-seating them reset the system. Then the same issue recurred. Re-seating the modules did not resolve this the second time. Only when the modules under the rear seat were removed and re-installed did the systems start again.