Urgent help: 12 volts for ignition lock

When installing Navi and repairing the window lifter right back, it turned out that apparently some circuits connected by the ignition lock have only 8 - 9 volts of voltage. (In any case window lifter, radio, here + switched). Surely, this is the responsibility of an aid relay. What's it called, and where exactly is it? Or what else can be the cause?