4x4 prob

[and11]

I asked this not long ago i didnt get a reply probely my fault .My 4ltr auto explorer 4wd is faulty when i switch to 4wd hi light comes on dash and stays on but no 4wd engaged switch to 4wd lo and light comes on dash but still no 4wd /lights dont flash but stay on as they should .could it be the gem unit or shift motor or worse

 

[IAmTodd]

What year?

 

[and11]

4x4 probs

my car is a 1999 explorer north face thanks for replying

 

[IAmTodd]

The locking of the center diff to provide power to the front propshaft is done with an electronic clutch. You need to ensure there is power being applied to it. The most simple test would be to jack the front up, turn the truck on (not running) and switch the knob to 4x4 Hi. Crawl underneath and attempt to rotate the front propshaft. If it does not spin it is locked to the input and output of the transferbox. Bad news is it sounds like a front diff problem.

If you you can spin it you need to verify if there is power to the brown wire located at the rear of the transferbox. There should be a connector that you can place the front of a multimeter in to verify there is ~12 volts.