While driving, the passenger rear window went down on its on and will not come back up. Why?

Replace the master switch assembly.

Rear Passenger Power Window Operation
The rear passenger power window switches receive battery voltage through the window lockout control circuit if the window lockout function is disabled. Ground for the rear passenger power window motors is supplied through normally closed up and down contacts of both the rear passenger power window switches and the driver power window switch. When the either rear passenger power window switch is placed in the down position, the power window motor down control circuit is switched to 12 volts and is applied to the down side of the rear passenger power window motor. Since the other side of the rear passenger power motor is connected to ground through the normally closed up contacts of both the rear passenger and driver power window switches, the window travels down. By placing the rear passenger power window switch in the up position, the polarity of the power window motor is reversed and the window travels up.
The rear passenger power windows can also be controlled from the driver power window switch.

Did you try pushing the lock out switch on the drivers master switch ?

Did the switch work before replaced battery ? 2008 CTS ? Cadillac ? These switches are inputs to a control module , DDM - driver door module . a computer of sorts . A lot of thing's can go wrong with these systems , broken power or ground circuits inside the rubber boot from the body to the driver door . Communication problems between control modules etc... Plus the power windows don't use fuse's , has a circuit breaker for front windows - PWR/WNDW circuit breaker 25 amp located in the fuse box under the back seat , Fuse's are used for rear windows - two 15 amp fuse's LT/REAR an rear ,both are in the rear fuse box under back seat. These rear windows are controlled by the BCM - body control module .

The power windows system consists of the following components:
• Driver door module (DDM)--GMLAN device that receives and transmits messages and signals for window functionality. The DDM contains the driver door switch (DDS) which is integrated into the module. The DDS contains the driver, front passenger, RR and LR window and window lockout switches.
• Passenger front door module (PDM)--GMLAN device that receives and transmits messages and signals for window functionality. The PDM contains the front passenger door switch (PDS) which is integrated into the PDM. The PDS contains the front passenger window switch.
• Left rear power window switch--Provides switched voltage and ground window switch signals to the left rear window motor for left rear passenger window operation
• Right rear power window switch--Provides switched voltage and ground window switch signals to the right rear window motor for right passenger window operation
• Left front power window motor--Contains position sensors and a module that receives signals from the DDM and provides a status signal to the DDM
• Right front power window motor--Contains position sensors and a module that receives signals from the PDM and provides a status signal to the PDM
• Left rear power window motor--Contains position sensors and a module that receives signals from the left rear power window switch
• Right rear power window motor--Contains position sensors and a module that receives signals from the right rear power window switch
• DRIVER DR MOD fuse (15-amp)
• PDM fuse (15-amp)
• PWR WNDW Circuit Breaker (25-amp) -- front
• LT/REAR/WNDW fuse (15-amp) -- rear
• REAR/WNDW fuse (15-amp) -- rear


Power Window Operation
The driver and front passenger doors are equipped with power window motors that contains its own module. Each power window motor receives a hot at all times battery supply voltage and constant ground source. When the right front passenger window switch on the DDS is activated to the up or down position, the DDM will interpret the signal and send a GMLAN serial data message to the PDM. Upon receipt of the message, the PDM will send a signal to the front passenger window motor module on the GMLIN serial data circuit. The window motor module will then supply battery voltage and ground to the window motor to drive the window motor to the up or down position.
The DDM communicates via the GMLAN serial data circuit with the body control module (BCM) to control the rear window functions from the driver master window switch. The BCM is hard wired to each rear power window switch with circuits for window up, window down, and an enable circuit. The rear window switches contain internal logic that when supplied with voltage from the BCM over the enable circuit will driver the appropriate window in the direction commanded.
The rear power window switches are supplied with battery voltage from individual right and left WNDW fuses located in the rear fuse block. When a rear power window switch is activated to the DOWN position, voltage is applied to the motor down circuit and the motor up circuit serves as the path to ground. The window motor will drive in the downward direction until the switch is released or the window has fully opened. When the window switch is activated to the UP position, voltage is applied to the motor up circuit and the motor down circuit serves as the path to ground. Ground for the left rear power window switch is supplied at G200 and the right rear power window switch receives ground at G201.

The power locks work the same .

After replacing the driver door switch (DDS) or passenger door switch (PDS), perform the programing procedure.

If you don't know any of what i posted your best bet , have a qualified repair shop check it out .

Possibly a faulty driver door switch. There is a function tied to switch allowing driver to open or close all windows through door switch.

I’m happy to assist further over the phone at https://www.6ya.com/expert/howard_977676954994c5b2

Take the door panel off. Common problem on ford trucks. You will see the window drive cable and the problem.

bad switch common on these dodges.

More than likely, the window regulator is bad. If you hear the motor "trying" to move, the regulator is bound up, or broken.

replace the window mechanism on that door

replace ur power window switches

i would pull the window switches up and test for power if you have power pull the front passenger side switch out and attach it to the rear connector if that still doesnt work i would pull off the door panel and look to see if the window motor arms are not connected if not your window motor may be damaged did the windows show any signs of going bad before it went bad like moving pretty slow or alot of movent forward and back while going up and down