How can I check to see if the 4x4 shift module has gone bad?

 

Shift it into four wheel drive.

 

^^Lol yup basically

If you ruled out everything else( hubs, drive shaft, transfer case, shift motor, switch) that would cause your 4x4 not to work then very well could be the module.

Check the fuse too.

 

Is a module an expensive fix?

 

What do you consider to be expensive ?

 

Before replacing anything related, check the pigtail wiring connector of the transmission. This signals the PCM and several other important functions. Replace if the connector (probably 12 wire), pins or wiring look less than perfect. It's something you can do for $19 and 5 minutes. Good idea to replace if it's the original unless it's absolutely perfect.

 

Have you checked the function of all the other components? Fuse good? Voltage to the switch? Is the shift motor on the t-case getting power but not working? Do your hubs lock(if they are auto hubs)?

You could pull a module from a junk yard for about 10$

 

Same guy same question same answers different thread
https://www.f150forum.com/f10/4x4-help-needed-173101/

 

Lol well that info would have been helpful. Guess its been covered

 

How does that thread "cover" it? All I got from it is someone saying the electric shift motors on the transfer case is "prone to failure". Am I not seeing the whole thread? It didn't cover anything.