1993 ford ranger 4x4 does not work and I need help

[Joe green]

I am working on a 1993 xlt. The symptoms are the 4x4 does nothing when the buttons are pressed. I'm not sure if the button 4x4 indicator light is supposed to turn on when the ignition is turned on but they do not. The shift motor is brand new. I followed every step in the https://www.therangerstation.com/tech/ford-ranger-4x4-module-diagnosis-1994-older/ post. Everything checked out until I get to the very end of the post where it said to check power being sent to the shift motor. I do not get any power being sent to the shift motor. In step 6 it says to check continuity between the 4x4 computer and the shift motor which i have. In 6a it says to check for 12v on the blue wire and check for 12v going to the switch. The issue is I have exactly 5v on the blue wire. Is that correct or should I have 12v on the blue wire?

 

[RonD]

No, on the 1994 and older there is no Bulb Test for the 4x4 system with key on, 1995 and up have that

Just a brief "how it works"
The shift motor has 2 power wires for the motor part, usually yellow and orange wires
And it has 5 "sensors" wires, nothing to do with movement of motor

In the 4x4 module there are two relays, one for each "power" wire, one for yellow wire and one for the orange wire
When the relays are off, BOTH of these wires are Grounded, you can test for that at the shift motor connector, 0 ohms to ground
If not then check the ground wires on the controller, one is unhooked, black and black/orange wires, pins 2 and 3

When motor needs to be moved then controller just needs to activate ONE relay to change its wire to 12volts
So motor now has 12v and ground wires, so spins
If the other relay was activated then motor has ground and 12v so spins the OTHER WAY
Exactly the same as a power window motor works, both wires are grounded all the time, one wire is change to 12v, which wire decides window up or window down

Then you press 4WD dash button you should HEAR one of the relays "click" if controller is "getting the message"

Below is the wiring colors for 1993 4WD system
Not sure what red wire you are referring to, wire colors do change

Did you press the button on the controller?
Did you check the fuse in engine bay?
There are TWO fuse #7s, one on the cab and one in the engine bay fuse box, BOTH power 4WD system
One in engine fuse box powers the shift motor
You need to pull out fuses all the way to make sure there is no corrosion, 'just looking' is great for girls, but not for fuses

 

[Joe green]

No, on the 1994 and older there is no Bulb Test for the 4x4 system with key on, 1995 and up have that

Just a brief "how it works"
The shift motor has 2 power wires for the motor part, usually yellow and orange wires
And it has 5 "sensors" wires, nothing to do with movement of motor

In the 4x4 module there are two relays, one for each "power" wire, one for yellow wire and one for the orange wire
When the relays are off, BOTH of these wires are Grounded, you can test for that at the shift motor connector, 0 ohms to ground
If not then check the ground wires on the controller, one is unhooked, black and black/orange wires, pins 2 and 3

When motor needs to be moved then controller just needs to activate ONE relay to change its wire to 12volts
So motor now has 12v and ground wires, so spins
If the other relay was activated then motor has ground and 12v so spins the OTHER WAY
Exactly the same as a power window motor works, both wires are grounded all the time, one wire is change to 12v, which wire decides window up or window down

Then you press 4WD dash button you should HEAR one of the relays "click" if controller is "getting the message"

Below is the wiring colors for 1993 4WD system
Not sure what red wire you are referring to, wire colors do change

Did you press the button on the controller?
Did you check the fuse in engine bay?
There are TWO fuse #7s, one on the cab and one in the engine bay fuse box, BOTH power 4WD system
One in engine fuse box powers the shift motor
You need to pull out fuses all the way to make sure there is no corrosion, 'just looking' is great for girls, but not for fuses

Yes I pulled the fuses out to verify them and the contacts were good. What about the 4x4 control switch feed. Should that be 12v or 5v. Mine only has 5v on it.

 

[RonD]

5v if you are talking about the dash switch

The 5v comes from the controller, usually on a white/blue wire
Then switch has 2 "return" wires, dark blue and orange/blue
no 5v on either "return" is 2WD
5v on Dark blue wire is 4high
5v on orange wire is 4low

There is no connection to the 4WD lights from the buttons, the 4WD bulbs have 12v with key on, but no ground
The 4x4 controller grounds each bulb once the shift motor has moved into the correct position

When testing leave the shift motor off the transfer case but plugged in, you can hear if its working, no its case does not need to be grounded to transfer case, all its wiring is self contained
There are no "sensors" in the transfer case, the shift motor has the 4 position sensors in it
2H, 4H, Neutral, and 4L sensors
5 wires, 1 control wire and 4 "returns", each of the 4 positions has OPEN or SHORT in each position

Seen here

Yellow/white wire is the control wire
Other 4 wires are either connected to yellow/white(short) or not connected(Open)
Controller applies voltage to the shift motor until it sees the correct open/short pattern for the position that was requested by the switch

If the shift motor is not working OR the open/short wires are not changing, when controller applies power, then Controller will stop the shift motor and start to Flash both 4WD lights

You, of couse, can not select Neutral on electric shift, Ford thought it was too dangerous for US morons, but its there

 

[Joe green]

5v if you are talking about the dash switch

The 5v comes from the controller, usually on a white/blue wire
Then switch has 2 "return" wires, dark blue and orange/blue
no 5v on either "return" is 2WD
5v on Dark blue wire is 4high
5v on orange wire is 4low

There is no connection to the 4WD lights from the buttons, the 4WD bulbs have 12v with key on, but no ground
The 4x4 controller grounds each bulb once the shift motor has moved into the correct position

yeah that was my concern whether the power from the controller going to the 4x4 switch was supposed to be 12v or 5v but now You verified its supposed to be the 5v I am getting.

 

[Joe green]

If the switch is supplying the proper 5v signal back to the 4x4 computer why wouldn't the relays click. The computer light blinks when the test switch is activated and you can hear the relays click.

 

[RonD]

That's the $100 dollar question when troubleshooting, lol
"Why doesn't it work?"

The switch is just 2 on/off switches so pretty easy to test and take off the table

Shift motor is a 12v motor, so can be tested by giving its 2 "power" wires 12v and ground, see if it moves, then reverse the 12v and ground to see if it moves the other way
Shift motor does have a physical limiter, so will only move so far one way, can't do 360deg, so needs to be tested 12v/gnd and gnd/12v to make sure it can move in both directions

You have 12v and Ground at the controller, so can unplugged the connectors and test the motor from there, that also tests the wires to the shift motor and from battery(12v) and the Ground at controller
Wires are shown in the diagram posted previously

4x4 Controller will have several failure modes, not all can be disregarded by it passing logic test or the fact relays "click"
So best you can do is to test what you can, to eliminate those things, and then replace what you can't test, which in this system is the Controller

And remember, "new" means NEVER EVER TESTED, not "it works", that's the new normal for new parts, especially electrical parts, WE are now the Quality Control Department for all companies selling "new" parts, WE test it, they replace it if it doesn't work

 

[Joe green]

Is the 4x4 switch in the dash a momentary switch or is it supposed to click? My dash switch only provides the 5v back to the shift computer while the switch is being held down. Also the 4x4 light doesn’t illuminate on the switch when the switch is getting pressed but maybe it won’t illuminate until the 4x4 computer sends the power to illuminate the switch once it’s in 4x4?

 

[RonD]

Can't remember off hand, it would work using either method, as far as design, but haven't tested one in many years, but I thought it was a toggle so stayed in the last position, so if you shut off the truck and then came back and restarted it would still be in the last setting, 2WD, 4high or 4low, because I don't think any year controller had a "memory" to retain it's last setting, just used Key on Switch position, no 5V(2WD), 5v(4high) or 5v(4low), that would make more sense

If it was momentary then on start up/restart the controller would see 0volts on both wires and shift to 2WD, which would be a pain if you wanted to stay in 4high, lol

The 4WD lights have no connection to the buttons
The lights are grounded by the controller, once the shift motor "sensors" show it is in 4high or 4low position, or no lights and 2WD

When you pressed the button(when its working) there would/should always be a delay before the light comes on, the light is a confirmation that transfer case/sensors are in correct position

With key on you can ground the bulb wires at controller to test each one

 

[Joe green]

Can't remember off hand, it would work using either method, as far as design, but haven't tested one in many years

The 4WD lights have no connection to the buttons
The lights are grounded by the controller, once the shift motor "sensors" show it is in 4high or 4low position, or no lights and 2WD

With key on you can ground the bulb wires at controller to test each one

ok. I did test the bulbs by grounding them at the controller and both high and low lights came on along with the 4x4 indicator on the cluster so i know the bulbs are good.

 

[RonD]

Good stuff

I added to my post

 

[Joe green]

Lets say the shift motor is bad even though its brand new. When I push the 4x4 switch shouldn't I still hear the relay click in the 4x4 computer as its trying to power the shift motor?