and backwards therefore a single latch motor 34 can drive the forward and backward motion of locking and unlocking a vehicle door 14 or latching and unlatching a vehicle door 14 a different latch motor 34 is typically used for each different door 14 so if the vehicle 10 has four doors 14 there would be a right front latch motor 36 a left front latch motor 38 a right rear latch motor 40 and a left rear latch motor 42 in an alternate embodiment one latch motor 34 could be used for locking latching the door 14 and a second latch motor 34 could be used for unlocking unlatching the door 14 with reference now to fig4 and with continued reference to fig1 to 3 one embodiment of an ecu 72 is shown an u201c h u201d bridge is a type of circuit that can be used to reverse the polarity of dc power to an electric component such as a latch motor 34 the h bridge circuit has four gates that work in sets of two so the voltage is applied in one of two different directions in some embodiments the h bridge can comprise a half bridge for several related components combined with a common half bridge that completes the h bridge for each of the related components several half bridges are shown which combine to make a complete h bridge circuit for each selected door 28 there is a left front half bridge 100 a right front half bridge 102 a right rear half bridge 104 a left rear half bridge 106 a theft security lock half bridge 108 a child security lock half bridge 110 a left common half bridge 112 and a right common half bridge 114 the h bridge and the latch motors.