Hello,
I ve read a lot of good advice from this forum before joining.
I am stumped.
I have a 2002 Ford Ranger with no 4wd. The 4wd lights briefly come on when I first start it.
I active the 4wd switch to 4 hi and 4 low. Nothing happens. I dont hear any clicking or any noise at all
I pulled the transfer case motor out and bench tested it with my booster pack and nothing.
I put a new transfer case motor in it. Still doesnt work
I ve checked for power to the transfer case motor and I have no power on heavy gauge orange and yellow wires. (back probed)Only ground.
I ve checked all the fuses under the hood and in the cab 13,5,10,9,11,28
I pulled a wiring diagram i found on this forum ( thank you for posting it) and (backprobed) checked voltage and grounds to all pins on the transfer case module. (I can reveal my findings for each wire)
The switch appears to be working with 3.9v 2.9v 1.7v
I replaced the module with a new module.
I still have nothing. What am I missing? I hope someone can help
Thank you

 

The Orange and Yellow wires from the truck side of the 8 pin connector should show up as Grounds all the time
Test for that with OHM meter
Those 2 wires are hooked to two relays, each has its own relay, in the 4x4CM, these are what you should hear "click" when changing 4WD status
Both relays are 5 pin so when inactive both are grounds, so the 4x4CM only activates one relay to get the shift motor to turn clockwise, because other wire is already a ground
And activates the other relay for counter-clockwise
Works the same as power window motors, 12v/gnd up, gnd/12v down, reverse polarity

4x4CMs were known issue on 2001-2011 Ranger 4x4s

When you turn key on all the lights in the dash should come on, thats a BULB TEST, nothing to do with any of the systems, just FYI
So 4WD light bulbs work

The 4x4CM controls those lights
If you select 4high, for example the 4x4CM should activate a relay, a click, if shift motor doesn't start to move then 4x4CM should start to FLASH the 4WD light indicating a problem
If the 4x4CM doesn't know "where the shift motor is pointed" then it will FLASH the 4WD lights as soon as you turn the key on, well after the bulb test, lol

On the shift motor are 5 more wires, those are the "sensors" that tell the 4x4CM "where the shift motor is pointed"
So if those are bad you would get flashing 4WD lights
If shift motor is not moving you get flashing 4WD lights

You don't get flashing 4WD lights if 4x4CM is off or not working
"New" means never ever, EVER , tested, doesn't mean "it works", not any more

2002 4WD wiring below

There are two versions of the 4x4CM, 2001-2005 and 2006 to 2011, they are NOT interchangeable

 

I do have continuity on both the orange and yellow wires.
I will order another "New" module tomorrow and let you know what I find
Thanks

 

Well, tonight I went ahead and replaced the control module with another new module.
The results are the same. No activation or Clicking from the module.
I did check both power and ground going to the module, along with power at the switch and everything appears to be there to activate the module.
Would you have any other Advice I could try?
Thanks

 

There really is nothing else

There are only those 3 parts
dash switch
4x4CM
Shift motor

no other external relays or other "switches", no other connections to the vehicle except 12v and ground

And 4x4CM clicking(activating) has nothing to do with shift motor, so if its not working then its either not powered on or not grounded

 

Ok, If I get this resolved I'll be sure to post the results. I appreciate the help

 

Hi Ron,
While doing some more research. I found this thread that was posted by rorischagrin.
His symptoms are identical to mine.
Question... On the Yellow/LT Blue Wire (signal return wire) When tested on mine It is showing as grounded. Should it be showing 5v?
Below is a link
https://www.ranger-forums.com/drivet...8/#post2174087

 

Yes, it would show as a Ground
The way the system works is that the other 4 contacts will either be connected to the Yellow wire(short, grounded) or they won't be(open, no ground)

This chart shows what each open or shorted(closed) contact means to the 4x4CM




This has nothing to do with 4x4CM operation, if for some reason the contact plate is not reading correctly the 4x4CM will flash the 4WD lights indicating a problem, "it's lost", it doesn't know the position of the shift motor/transfer case

Say it was in 2wd and was told to change to 4high
4x4CM would close a relay inside("click") and then "watch" the orange/white(O/W) wire to see if it changed from open to closed instantly, if not it would open the relay(stop the motor) and flash the 4WD lights indicating a problem

 

Thanks for staying with me on this. Your answer makes sense to me.
However, When testing, I'am seeing voltage between 11.3V-11.6v on the wires Pin 4-7 regardless what position the switch is in.
Including Yellow White motor 1 wire.
And I am not getting any 4x4 flashing dash light either.
It'll only flash once when I first start it. (bulb check)

 

In the 2002 4WD wiring diagram pins 4 and 7 are the motor wires, Yellow and Orange, at the shift motor end, both should show as Grounds with key on, only 1 should show as 12v but only when 4x4CM tries to move the shift motor to another position

In fairness I have never pulled apart a 4x4CM to see if Ford changed the method for controlling shift motor with the dual relays
They could be sending 12v on both wires all the time and then ground one wire to make the motor turn, but that would make no sense at all to have 2 12v wires on with key on and be exposed to shorting out when you can do the same thing with ground on each wire....................

If you unplug the 4x4CM the 12v goes away, correct, so wires aren't shorted to 12v somewhere?

And you say the yellow/white wire(pin 6) has voltage or no voltage key on?

 

Yes voltage goes away with module disconnected
yellow/white has voltage with key on (11.7v)

 

I thought Ford always used the ground to test open/closed but maybe they didn't on the 2001 and up units

Your battery voltage is low, expected is 12.3v to 12.8v
But not the problem with the 4WD
Not sure what is

 

I appreciate your effort. Thank You