All 4 locks will unlock but will not lock what can i check

There is no separate fuse for power windows:
https://www.2carpros.com/questions/nissan-altima-2006-nissan-altima-windows-and-locks

https://oards.com/causes-of-power-windows-not-working/

Could be any number of thing's causing this problem . Knowing what all is involved in the locking an unlocking of the doors is key . Computer controlled by the BCM - body control module , relays ,wiring ,switches etc... Bad input from switch or grounding wire to the BCM could make the BCM think door unlock has been requested .
Door Lock System Components
The power door lock system consists of the following components:
• Driver door lock switch--Provides a switched voltage signal to the body control module (BCM) for both lock and unlock switch activations.
• Front passenger door lock switch--Provides a switched voltage signal to the BCM for both lock and unlock switch activations.
• Door lock relay--Located in the instrument panel (I/P) fuse block and controls the locking of all doors and liftgate.
• Door unlock relay--Located in the I/P fuse block and controls the unlocking of the passenger doors and liftgate.
• Driver door unlock relay--Located in the I/P fuse block and controls the unlocking of the driver door.
• BCM--Class 2 module which requires programming when replaced
• Reversible door lock actuators in each of the doors
• LOCK/MIRROR 10 A fuse--Located in the I/P fuse block, supplies power for the door lock switches and relays.
• DR LCK 20 A fuse--Located in the I/P fuse block, supplies power to the relays

Door Lock System Controls
The power door lock system can be controlled by any of the following:
• Power door lock switch activation
• Keyless entry lock or unlock command
• Delayed locking command
• Automatic door lock command
• Lockout prevention command
• An air bag deployment
Door Lock and Unlock Operation
When a door lock switch is activated in the lock or unlock position the body control module (BCM) will receive a voltage signal on either the door lock switch lock or unlock signal circuits.
The BCM, upon receipt of a lock switch lock or unlock signal, will switch the appropriate lock relay control circuit(s) to battery positive voltage. This will energize the appropriate lock or unlock relay(s). The relay will supply voltage to the door lock actuator lock or unlock control circuits to one side of the lock actuator. Since the opposing side of the lock actuators are connected to ground through the other lock actuator control circuit and the normally closed contacts of the lock or unlock relay, the doors and liftgate will then lock or unlock appropriately.
Three relays are used to operate the lock. Driver door unlock, passenger door unlock and all door lock. This is done to isolate the driver door lock actuator so it can be unlocked by itself using the keyless entry transmitter.

Automatic Door Lock Operation
This body control module (BCM) controlled feature can be personalized to driver preference.
The BCM will automatically lock the vehicle doors if the following conditions exist:
• All vehicles doors are closed.
• The ignition is in the ON position.
• The vehicle is shifted out of PARK.
The BCM will then unlock the doors when the ignition is placed in the OFF position.

The first thing ,hook up a professional type scan tool an check for DTC'S in the BCM
DTC Descriptors
DTC B3140 00: Driver Unlock Switch Circuit
DTC B3145 00: Passenger Unlock Switch Circuit
DTC B3150 00: Driver Lock Switch Circuit
DTC B3155 00: Right Front Lock Switch Circuit

DTC B3130 00: All Door Unlock Circuit

Check for broke wires inside the boot from body to driver door , this is a common problem . If you don't find broke wire's , pull the door panel to get at driver door switch . Check for voltage an ground circuit .
Rendezvous Door Lock System Components
The power door lock system consists of the following components:
?€¢
Body control module (BCM)

?€¢
Driver door lock switch

?€¢
Front passenger door lock switch

?€¢
Door lock actuators in each of the doors

?€¢
Door lock system fuse into the BCM (BCM D 25A fuse)

Door Lock Operation
When the BCM detects a transition of either of the door lock switches to the LOCK position, it switches the door lock actuator lock control circuit to voltage. Since the lock actuator unlock control circuits are at ground potential within the BCM, the door lock actuator motors transition to the Lock position.
Driver Door Unlock Operation
When the BCM detects a transition of either of the door lock switches to the UNLOCK position, it switches the driver door lock actuator unlock control circuit to voltage. Since the door lock actuator lock control circuit is at ground potential within the BCM, the LF door lock actuator motor transitions to the Unlock position.
The driver door lock actuator unlock control circuit is a dedicated control circuit used only for the driver door lock actuator motor. This is done so that the driver door may be unlocked by itself using a keyless entry transmitter or an automatic door unlock function (if programmed).
Passenger Door Unlock Operation
When the BCM detects a transition of either of the door lock switches to the UNLOCK position, it switches the door lock actuator unlock control circuits to voltage. Since the door lock actuator lock control circuit is at ground potential within the BCM, the passenger door lock actuator motors transition to the Unlock position.
The door lock actuator unlock control circuits are dedicated control circuits used only for the passenger door lock actuator motors. This is done so that the driver door may be unlocked seperate from the passenger doors using a keyless entry transmitter or an automatic door unlock function (if programmed). This video on testing computer controlled door locks on a Subaru , doesn't matter . test yours same way > The BCM controls your door locks .
Are all of the power door locks inoperative from both door lock switches?

Door Lock and Unlock Operation
When a door lock switch is activated in the lock or unlock position the BCM will receive a voltage signal on either the door lock switch lock or unlock signal circuits.
The BCM, upon receipt of a lock switch lock or unlock signal, will switch the appropriate lock relay control circuit(s) to battery positive voltage. This will energize the appropriate lock or unlock relay(s). The relay will supply voltage to the door lock actuator lock or unlock control circuits to one side of the lock actuator. Since the opposing side of the lock actuators are connected to ground through the other lock actuator control circuit and the normally closed contacts of the lock or unlock relay, the doors and liftgate will then lock or unlock appropriately.
Three relays are used to operate the lock. Driver door unlock, passenger door unlock and all door lock. This is done to isolate the driver door lock actuator so it can be unlocked by itself using the keyless entry transmitter.
Your door locks are controlled by the BCM - body control module (a computer ) . An a scan tool is a must to diagnose system operation . Your best bet would be to take your vehicle to a qualified repair shop . The only way you could try to fix this is by changing parts ! Suppose you find an replace a door lock/ unlock relay an that doesn't fix it ? There could be DTC'S stored in the BCM . Do you know what a DTC is ?
?€¢
DTC B3132 All Door Unlock Circuit Low

?€¢
DTC B3133 All Door Unlock Circuit High

Your

Pull the door panel apart and check and see if the pun that locks and unlocks the door is connected, if so check the power supply the the actuator.

It's only an educated guess. If all other locks switches are working it' either the switch panel itself or an electrical short. Switches are popular, get it checked first

The power door locks are controlled by the BCM -body control module ! The door lock switch is an input to the BCM .
The BCM, upon receipt of a door lock switch lock or unlock signal, will switch the appropriate door lock actuator control circuits to battery positive voltage. The opposing side of the door lock actuators are connected to ground internally within the BCM through the other door lock actuator control circuit and the doors will lock or unlock appropriately.
First thing to do would be check power an ground circuits at the BCM ! Do you have any other systems not working -power windows etc...
The DR/LCK fuse supplies battery positive voltage to the I/P fuse block for the door lock system. The body control module (BCM) supplies and monitors a reference voltage to the door lock switch through the door lock switch lock/unlock signal circuit. The door lock switch also receives a constant ground source. If a door lock switch is placed in the lock position or unlock position, the reference voltage is taken directly to ground and the BCM detects the voltage drop on the signal circuit.
Should have BCM checked for stored DTC'S - diagnostic trouble codes !
Ignition ON, observe the scan tool Driver Door Lock Sw, Psgr Door Lock Sw, Driver Door Unlock Sw and Psgr Door Unlock Sw parameters while using the driver and passenger door lock switches. The parameters should change between Active and Inactive.
?‡'
If the values does not change between the commanded states, refer to Door Lock Switch Malfunction.

Command the driver door and passenger door lock actuators to LOCK and UNLOCK with the scan tool, the doors should LOCK and UNLOCK when changing between commanded states.
?‡'
If a door lock actuator does not perform the LOCK and UNLOCK functions, refer to Door Lock Malfunction

DTC B3130 00: All Door Unlock Circuit

DTC B3135 00: All Door Lock Circuit

check for a short or a bad wire sounds like a bad conection check your conections

Programming
When
Key added or replaced. System malfunction.
How
Obtain all keys. A maximum of 3 keys can be programmed. Close all doors and boot/tailgate. Switch ignition ON. Repeat procedure below 3 times: Within 4 seconds: Press key lock or unlock button. Within 4 seconds: Switch ignition OFF. Within 4 seconds: Switch ignition ON. Within 4 seconds: Press key lock or unlock button. System should now lock or unlock vehicle. Within 4 seconds: Press key lock or unlock button. Within 10 seconds: Press lock or unlock button of first key. System should now lock or unlock vehicle. Press lock or unlock button of second key. System should now lock or unlock vehicle. Press lock or unlock button of third key. System should now lock or unlock vehicle. Switch ignition OFF. Remove key. Check operation of all programmed keys.
NOTE: If less than 3 keys are to be programmed, remove ignition key after programming last key.