The lighting intensity of all annunciators and P/BSWs on the overhead panel, glareshield and pedestal, can be decreased (dimming) with the "TEST-BRighT-DIM" control switch installed on the overhead panel. Four identical transformers distributed through control cards to the P/B lamps supply the correct voltage. These transformers are installed in the avionics bay, on the right hand side, between frames 8 and 11.