I don't know position to switch on the button for my Nissan mistral automatic transmission

The neutral safety switch on an automatic transmission (also known as a park/neutral position switch or neutral start switch) is usually mounted to one side of the shift lever (top of the transmission), around the base and near the bottom (front-wheel drive models); other models have the switch attached to the left

Possible causes Faulty Automatic Transmission Fluid (ATF) Pressure Switch 1 Automatic Transmission Fluid (ATF) Pressure Switch 1 harness is open or shorted Automatic Transmission Fluid (ATF) Pressure Switch 1 circuit poor electrical connection

http://pdf.textfiles.com/manuals/AUTOMOBILE/NISSAN/frontier/2007_Frontier/at.pdf

see pg 160 on the above link

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I would check the ignition switch

See pg. 3-31 in owners manual. Start car in park. Adjust seat, telescoping wheel, and side view mirrors. Pust Mem button and then within 5 sec. push either 1 or 2. That button should light to show memory stored.
From the 2012 Guide (See link)
l"AUTOMATIC DRIVE POSITIONER (if so equipped) Two positions for the driver's seat, steering column and outside mirrors can be stored in the automatic drive positioner memory. Follow these procedures to set the memory positions: • Confirm the shift lever is in the P (PARK) position. • Push the ignition switch to the ON position. • Adjust the driver's seat, steering column and outside mirrors to the desired positions using the adjusting switches for each feature. • Push the SET switch and within 5 seconds, push the memory switch (1 or 2) for at least 1 second. • The indicator light on the memory switch you select will illuminate for approximately 5 seconds. • The driver's seat, steering column and outside mirror positions are now set to your preference. These memorized positions can also be linked to your NISSAN Intelligent Key®. For more information, refer to the "Pre-driving checks and adjustments (section 3)" of your Owner's Manual." https://owners.nissanusa.com/content/techpub/ManualsAndGuides/Murano/2012/2012-Murano-quick-reference-guide.pdf
For added info see whole owners manual.

code p1760 refers to park/neutral position switch (PNP) circuit malfunction=== causes --wiring --PNP switch--- ECM
basically check that the wiring is in good condition and that the connections are tight and clean , replace the swutch

there is not a separate battery for the transmission, if your cars battery goes dead or is disconnected you can manually unlock the shifter.
if by chance it is stuck and the battery is good you could have a bad brake switch or a bad relay.

Shift - interlock system problem .
Automatic Transmission Shift Lock Control System
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of PARK position. The system consists of the following components:
• The automatic transmission shift lock control solenoid
• The automatic transmission park lock solenoid
• The automatic transmission shift lock control switch
• The transmission range switch
With the ignition in the ON position, battery voltage is supplied to the automatic transmission shift lock control switch. The circuit continues through the normally-closed switch to the automatic transmission shift lock control solenoid. The transmission range switch provides a path to ground for the automatic transmission shift lock control solenoid in the PARK position. With the automatic transmission shift lock control solenoid energized the shift lever is mechanically locked in the PARK position. When the driver presses the brake pedal, the contacts in the automatic transmission shift lock control switch open, de-energizing the automatic transmission shift lock control solenoid. This allows the shift lever to move from the PARK position. When the shift lever is out of the PARK position the controlled ground contacts in the transmission range switch open. This prevents the automatic transmission shift lock solenoid from energizing when the vehicle is out of the PARK position.

The switch that controls the backup lamps on a 1996 Nissan Pathfinder looks completely different and is in a slightly different location depending on whether the vehicle is equipped with a manual or automatic transmission. However, in ether case, the switch is located on the transmission.

On the manual transmission it is called simply, "backup switch".
On the automatic transmission it is part of the "inhibitor switch". (also known as "neutral safety switch")