Voltage is applied at all times through the R/CMPT REL fuse in the underhood accessory wiring junction block to the transaxle range switch through circuit 840. When the transaxle is shifted into REVERSE, voltage is applied through the closed contacts of the transaxle range switch, to the RH and LH backup lamps through circuit 24. The backup lamps are grounded through circuit 250 to G401 (LH) and circuit 350 to G302 (RH).