4 wheel drive issues

Maintenance/Repairs
1

Hey guys I’ve got a 2002 Ford explorer sport 4 wheel drive and the 4 wheel drive has stopped working. It worked fine a year ago when I bought it but has stopped working. Is there a fuse that could have blown and stopped it from working?

2

looking at the ford explorer chat rooms there is a fuse for that, start there. Any flashing lights?
Here is a possible help forum to explore.

3

Corrosion is common on rarely used electrical systems.
Switch, relay, shift motor and every plug in the series may be a corrosion fault.
Inside the switch or relay is pretty hard to tell but ( after checking the fuse ) start by UN-plugging and RE-plugging components along the chain of command.
not a real easy job to prove out if there’s a completely bad component without knowing the circuits to test and when.

    • this brings it to a shop. - -

The reason I speak of corrosion over time goes back to my 92 Explorer.
twice . . with lack of use over mild winters and of course summers . . . my switch did nothing too.
When a tech traced it to the shift motor not engaging . . I tried an experiment.
Since it was my own truck, if the experiment failed, it was just my own time spent.

    • on the shift motor
      where the wires enter through a cover with three screws. .
      I took off the cover . . cleaned the contact fingers inside . . Re-assembled ( careful to align the cap right )
      and . . ?
      A working shift motor once again.

not to say this is your problem , but it sure sounds all too familiar.

We soon discovered that off-the-books solution to be an answer to many ( not all ) diagnoses of a bad shift motor.

4

Here is an exchange between a mechanic and some one with the same problem…

the most common problem for this year and vehicle is the 4x4 module goes bad and needs to be repalced
Steve :
If the light is not coming on and no4x4 more than likely the module needs replaced
JACUSTOMER-h0em0b6h- :
Is a module the same as a sensor and therefore something a mechanic needs to replace
Steve :
no the module is the computer under the passenger side dash
Steve :
It is easy to replace but I would recommend diag first
JACUSTOMER-h0em0b6h- :
No warning light on module going bad and I guess explains why the it the auto 4wd doesn’t engage
Steve :
check for codes with a special tester that most shops have
JACUSTOMER-h0em0b6h- :
Sounds like I need an appointment with ford to run diagnostics and replace module
Steve :