Were is the axle actuater located at and how to install

try moving by hand and or removing and lubing

Make sure power available from actuator switch to transfer box, all connectors are secure. Look in owner manual fuse location .

Your best bet , take it to a qualified repair shop , before you replace more part's that arn't needed . Did you check to see if any DTC'S - diagnostic trouble code's are stored in the transfercase control module . Which transfer case does it have ? How many buttons on the instrument panel 4X4 switch ?
The NVG 236/246 transfer case features a 4 button shift control switch located on the instrument panel.
Do you know what a DTC is ?
DTC C0367
The front axle control circuit consists of an electric motor actuator which engages and disengages the front axle. The front axle actuator's motor consists of a Permanent Magnetic (PM) motor, a worm gear controlled plunger, a front axle switch and an electronic control circuit all within the actuator assembly.
The front axle actuator has four circuits connected to it, a front axle feed circuit, front axle ground circuit, front axle control circuit, and a front axle switch circuit.
Whenever a shift to AUTO 4WD, 4HI, or 4LO is requested, the automatic transfer case control module engages the front axle by grounding the front axle control circuit through a current limiting driver.
This DTC detects a shorted actuator, or a short to 12 V on the Front Axle Control Circuit.

Your vehicle can set a number of them .
DTC B2725
DTC C0300
DTC C0305
DTC C0308
DTC C0309
DTC C0310
DTC C0315
DTC C0323
DTC C0324
DTC C0327
DTC C0362
DTC C0367
DTC C0374
DTC C0376
DTC C0387
DTC C0550
DTC C0611
Without a professional scan tool an factory service repair info. you really shouldn't be trying anything , take it to a qualified repair shop.
The NVG 263 transfer case features a three button shift control switch located on the instrument panel.

New Venture Gear 263 Selectable Two Speed Transfer Case
The NVG 263 transfer case features a three button shift control switch located on the instrument panel. When the vehicle has the ignition key in the RUN position, the transfer case shift control module starts monitoring the transfer case shift control switch to determine if the driver desires a new mode/gear position. At a single press of the transfer case shift control switch, the lamp of the new desired position will begin flashing to inform the driver that the transfer case shift control module has received the request for a new mode/gear position. The lamp will continue to flash until all shifting criteria has been met and the new mode/gear position has been reached (or has been engaged). Once the new mode/gear position is fully active, the switch indicator lamp for the new position will remain ON constantly.

Gordon, I will take a guess, the Vacuum shift actuator/motor is located on the front axle. Check the attached pictures of actuator and how to replace video,links,instruction and guides, Good luck
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Diagnosing 4WD Engagement Problems on Dodge Ram pickups
Front Drive Axle 4wd Vacuum Disconnect Motor 1AFWA00007
Front Axle 4 Wheel Drive Actuator Replacement 4x4 Dodge Ram

the front axle actuator is stuck engaged. the actuator is located on the right side of the front axle. the part is easily replaceable.

The 4wd shift knob should be on the floorboard, the actuator that sends the power to the front axle would be an internal part of the transfer case

i had the same problem with my 1996 ram. I ended up having to change the vacuum actuator on the front axle .it is located on the axle to the right side of the differential housing . Mine actually had a pinhole rusted through. It is easier to replace the mounting bracket and the actuator at the same time .

The Selectable Four Wheel Drive (S4WD) Front Axle consist of the following components:
• Differential Carrier Housing
• Differential Case Assembly
• Inner Axle Shaft
• Intermediate Shaft Bearing Assembly (located on the right side of the oil pan)
• Electric Motor Actuator
The front axle on Selectable Four Wheel Drive (S4WD) model vehicles uses a disconnect feature mounted on the right side of the oil pan in order to engage and disengage the front axle. When the driver engages the 4WD system, the Transfer Case Control Module sends a signal to the electric motor actuator to energize and extend the plunger inside. The extended plunger moves the clutch fork and clutch fork sleeve across from the clutch fork outer gear that is splined to the right side wheel drive shaft to the clutch fork inner gear that is splined to the inner axle shaft. The locking of the two gears allows the axle to operate in the same manner as a semi-floating rear axle. A propeller shaft connects the transfer case to the front axle. The differential carrier assembly uses a conventional ring and pinion gear set to transmit the driving force of the engine to the wheels. The open differential allows the wheels to turn at different rates of speed while the axle continues to transmit the driving force. This prevents tire scuffing when going around corners and premature wear on internal axle parts. The ring and pinion set and the differential are contained within the carrier. The axle identification number is located on top of the differential carrier assembly or on a label on the bottom of the right half of differential carrier assembly. The wheel drive shafts are completely flexible assemblies consisting of inner and outer constant velocity CV joints protected by thermoplastic boots and connected by a wheel drive shaft.

How To Install Repair Replace 4x4 Front Axle Actuator Chevy Trailblazer...

there is a actuator under the battery that pulls a cable to the front axle when in 4 wheel drive see if you have vacuum to the actuator if not look on the transfer case that is where the valve is located they go bad often

This is something you can do yourself if you have ever worked on a vehicle before. The part you need is called a front drive actuator valve. It costs about $ 50.00, GM part # 15165891.
Here is some more infor about it:

Main 4wd Components:
TCCM - Transfer Case Control Module - Located behind the glove box. This is the electronic 'brains' behind the shifting.
Switch - The push button switch in the dash - driver input/indicator.
Encoder Motor - Located on the transfer case - This is what actually shifts the transfer case, and tells the TCCM what position it is in.
Vacuum Switch - Also located on the transfer case - This is what sends vacuum to the vacuum actuator (see below) when the transfer care is in 4HI or 4LO.
Vacuum Actuator - Located under the battery tray - This is what engages or disengages the front driveshaft.
Front Axle Switch - Located on the front axle - This is what tells the TCCM when the front axle is engaged.

If you want to try and replace it yourself, please let me know how it goes.