2004 ford ranger 4.0 changed 4x4 module after checking all fuses $180 invested in module that i probably didn't need don't know what to do next.what about switch or is there a relay ?

 

Welcome to the forum

I assume you are having a 4x4 related problem, since you replaced a part related to 4WD, what was the part number of that module?

Can you describe the problem?
Only 2WD, no shift to 4WD even though light comes on
Flashing 4WD lights when you try to shift
Flashing 4WD lights all the time
2WD and 4High work but no 4Low


When you first turn on the key 4WD lights should come on, testing the bulbs, then go off, does that happen?

 

The lights for 4x4 and 4low do cycle on when you start the engine all fuses are good new 4x4 cm should it have power to the switch VI

 

The 4WD switch it just 3 resistors, there may be a low voltage on the white/blue stripe wire, maybe under 5volts.

The 20 amp fuse in the Engine fuse box powers the Shift motor on the transfer case, but that power does run thru the 4X4CM
4WD lights should flash if that was blown

And lights should also flash if shift motor itself wasn't moving.

System operates fairly simply
When you turn on the key the 4X4CM gets power and turns on the 4WD lights then turns them off if in 2WD
If you select 4High with switch then 4X4CM sees resistance change and sends 12volts to the shift motor
Shift motor has 5 contact switches inside that tell the 4X4CM the position of the transfer case shifter.
If 4X4CM doesn't see these contacts changing while it is sending the motor 12 volts then it will start flashing the 4WD lights.

Or if after key on the 4X4CM detects open circuits, it will flash 4WD lights.

So yes you could have a bad switch or wire, but I would expect flashing 4WD light

 

Getting a new switch tomorrow will let you know if it does the trick