I drove 1994 BMW 740IL and the passenger side mirror usually will move down when i put my car on reverse so i can see the curb view, however it stop working just now when i get in my car to back out from a parking lot. What is went wrong ??

The passenger mirror system is designed to point down when reversing- if the mirror adjust switch is to the driver side. If you don't wish to have it do this, keep the adjust selector switch pointed to the passenger side. If that switch is malfunctioning it could also explain why you cannot adjust the driver's mirror.

Mirror Tilt in Reverse Controls
This feature is capable of tilting the passenger side power mirror when the transmission is placed in reverse to provide enhanced visibility during parking or backing maneuvers. This feature is turned OFF or ON through the DIC. The passenger mirror on domestic vehicles can not be changed from the factory setting, but on export vehicles, the passenger mirror position may by changed using the same procedure as the driver mirror. For further information, refer to Driver Personalization in Personalization.

Tilt Mirror In Reverse
Continue with the following steps in order to personalize the tilt mirror in reverse.
Press the Select button in order to enter the menu. The first choice seen is the current setting.
Press the Select button in order to scroll through the following options:
• CURB VIEW: OFF (Default)
• CURB VIEW: PASSENGER
Press the Personalization button in order to advance to the next option.

sounds like a short between the mirror control wire and the passenger side unlock wire, probably the wires have rubbed trough the insulation, you have to locate the wires and put some insulation tape on the spot they have rubbed trough,

Shift to reverse, adjust the mirror for normal, and save that to memory for that operator. This is presuming that you have not found a setting to turn off reverse mirror settings.....

Replace mirror assembly

I researched the maintenance manual. The fuse you need to replace is fuse 20 in the under dash fuse box. It controls side windows, washer motor, rear view dim function, and possible seat memory. There are a couple that link to the mirrors, but this is the one for this problem.

in the glove compartment