2002 Explorer doesn't shift into 4wd

[Hunter3006]

New to the forum. I have a 02 explorer Limited with electronic 4wd buttons. When I try to shift into 4x4High or low nothing happens. I get no indicator lights on the dash ( dash lights do work when I start the vehicle). I've check all the fuses that are listed in the owners manual and they seem to be good. Anybody have a step by step diagnostic procedure for this problem?

 

[TechGuru]

be sure the buttons are actually connected. If someone has ever swapped radios they may have forgotten to reconnect them.

Does the light flash when you hit 4x4 low?

 

[Hunter3006]

Thank you for your reply. No the radio has never been out, and the 4x4 low light does not flash.I diddo

 

[Hunter3006]

Sorry sent the above post before I was finished. I did do some engine work last September (replaced valve cover gaskets) in which I disconnected the Negative battery post. After that my CD player wouldn't play.

 

[rrgone]

Have a look through this thread: 4x4 does not work

You will see that that the 2002's have control modules that fail, often after the battery is disconnected. Sometimes the ground to the transfer case shift motor becomes corroded and loses grounding contact so check that first before getting a new CM.

 

[Hunter3006]

Okay, I'll check the ground first. Is the ground connected to the motor separately or in the connector? Is there any other ground cable I should check? Thanks for the advice.

 

[TechGuru]

 

[Hunter3006]

Thank you for the electrical print. I haven't had time to check the ground wire yet. I did do some experimenting today. I was on a snow covered dirt road so I stop and put my window down to watch my front wheel, when I hit the accelerator I had all four wheels spinning, when I pushed the 4hi button there was no dash light but all wheels spun. When I pushed 4low the light flashed and I heard the clunk like it shifted but when I hit the accelerator it didn't seem like it shifted in to low and the light stop flashing, also no dash light.

 

[TechGuru]

Thank you for the electrical print. I haven't had time to check the ground wire yet. I did do some experimenting today. I was on a snow covered dirt road so I stop and put my window down to watch my front wheel, when I hit the accelerator I had all four wheels spinning, when I pushed the 4hi button there was no dash light but all wheels spun. When I pushed 4low the light flashed and I heard the clunk like it shifted but when I hit the accelerator it didn't seem like it shifted in to low and the light stop flashing, also no dash light.

You have to be in neutral with your foot on the brake to shift into 4x4 low.

 

[Hunter3006]

Thank you for all the instructions. I did some experimenting today. It will shift into 4hi and 4low. I confirm this the same way I did yesterday only on a snow covered field. but I wasn't sure it always shifted back to auto 4x4 from 4hi. Going from 4low to auto seem to work every time except sometimes it seemed as if only the rear wheels would spin. Going from 4hi to auto the front wheels always spun. I took it out on the hard road to see if the if the front wheels would try to hop, to see if it was stuck in 4hi but when I made a couple of tight turns it drove fine and didn't hop. I still do not have any indicator dash lights to tell me if I'm in one of the 4x4 modes.

 

[h82loseejr]

You are having same issue that I had. After swapping the transfer case The case woudl shift (this only happens going from high to low) but no power to front axle. There is an "electroviscus" clutch between front drive shaft and rear drive shaft/ 4wd is "engaged" at all times. When computer senses speed difference between front drive shaft and rear drive shaft it applies voltage to the "clutch" engaging the 4WD.......you need to do is get a Electrical Volt meter set to VDC test if the clutch is engaging. You will be testing the BROWN PIN 16 AND DARK GREEN PIN 11 I forget the "exact voltage" but i think it is 0v to 5v....zero being axle is free to move.....5v being full lock up....(it may be 0-12)....so jack vehicle up...and engage 4wd you should have power between those 2 wires...if you do not...test each wire to a good known ground...one should be powered....and the other the ground...when you find the one with power (vehicle side) then switch to OHMS scale....test the other wire (if you find power on brown wire then test green) between pin on vehicle side and known good ground... Mine ended up being wire terminal broken off on ground wire....on vehicle side ground comes out of the plug and then behind a bolt right there on transfer case....if you have a goo ground then test between the wires (transfer case side) you should read something like 10 ish ohms...if it says OL...then your tc is shot

 

[Hunter3006]

Thanks I'll test those wires as soon as I get a chance. I may not have been clear in my last post. When I started this thread I thought that my explorer was not shifting into 4wd. After some experimenting I found out It will shift into 4wd hi and low and I do have power to the front axle. What I'm not sure of now, is if it's shifting back to 4auto from 4hi, I still have power to the front axle after pushing the button to shift back to 4auto. It seems to shift from 4low to 4auto ok, but when in 4auto it seems to take some time to get power back to the front axle when the rear wheels spin. Is that normal? Also my 4hi and 4low indicator dash lights come on only when starting the vehicle. They do not come on when shifting into 4hi or low.

 

[h82loseejr]

The computer senses difference in speed from the front to rear driveshaft...There is no 2wd per se...The electrovisous clutch is locked on in 4high...in 4 auto it varries voltage and applies more power for more slip...its kinda like a standard shift car when your taking off in first gear and letting the clutch out...if you floor it a lot of rear tire spin it locks 1:1...if you say just barely start spinning...it applies power to the front to stop the rear spin...We had ours lock up and not allow any slip in 4 auto...the cluch locked right up....could tell on dry pavement when turning in 4 auto....So in order to test if it is a control issue (computer telling it to lock up) or if it is a mechanical issue in the transfer case....Unplug the transfercase electrical connector....just un plug it and let it hang...then drive vehicle...if it seems like its still locked up then you need to replace the transfer case...if it seems like it is normal then you have a issue with computer telling it to lock up

 

[h82loseejr]

The computer senses difference in speed from the front to rear driveshaft...There is no 2wd per se...The electrovisous clutch is locked on in 4high...in 4 auto it varries voltage and applies more power for more slip...its kinda like a standard shift car when your taking off in first gear and letting the clutch out...if you floor it a lot of rear tire spin it locks 1:1...if you say just barely start spinning...it applies power to the front to stop the rear spin...We had ours lock up and not allow any slip in 4 auto...the cluch locked right up....could tell on dry pavement when turning in 4 auto....So in order to test if it is a control issue (computer telling it to lock up) or if it is a mechanical issue in the transfer case....Unplug the transfercase electrical connector....just un plug it and let it hang...then drive vehicle...if it seems like its still locked up then you need to replace the transfer case...if it seems like it is normal then you have a issue with computer telling it to lock up

 

[h82loseejr]

the motor on the transfer case only shifts between 4 high and 4 low....so it will not move at all going between 4auto and 4 high....going between auto and 4high only locks the clutch not shift transfer case. When ours went bad it was summer and I just removed front drive shaft...the front axle has no hubs or means to unlock like other 4wd systems...even in 4 auto the driveshaft turns with the wheels...it unlocks in the transfer case...so with the front wheels off the ground and rear wheels on the ground you shoudl be albe to turn the front drive shaft with the vehicle turned off...again another test to see if that clutch is locked in

 

[Hunter3006]

Thanks for the advice, I will look at it some time this weekend. Any thoughts on way the dash light don't come on when it shifts into 4wd?

 

[h82loseejr]

I think mine was doing same thing because the ground was off of the clutch..I cannot exactly remember. But if tthe clutch is locked up and not coming out of 4x4 and no light there may be more than one issue. There are a few threads on here on this issue.

 

[IIGood]

You have to be in neutral with your foot on the brake to shift into 4x4 low.

Well, thank you for this, and the instructions. My '03 is lacking an owner's manual and as long as I've owned this one, I just assumed the truck had to be in PARK to switch between 4x4 modes. I would put it in park and it would go into 4 HI just fine, but 4 LOW always resulted in the light on the button just flashing constantly. Today I tried it via the PROPER MEANS and it actually works.

 

[h82loseejr]

4x4 auto and high there is no "shift" it just locks the clutch...Can be done going under say 40 mph....in order to shift into 4low you have to be stopped and in neutral

 

[Mbrooks420]

You should be able to shift into high as fast as is safe to drive since all of the drive components are up to speed. It sounds to me like everything is working correctly, you just have an issue with the indicators.

Do the lights illuminate when you first turn the key to on?