4WD engages as soon as i drive off

[wskisoft]

Hi All,

I originally start with this tread ( http://www.explorerforum.com/forums/showthread.php?t=217536 ) but have since done the Brown Wire Mod which has made the truck usable again.

I have reconnected the wires from the transfer box and all is working. When I select 4wd I here the clicks and the light on th edash comes on. If I put the truck in N and select Low, I hear a loud clunk and the low is selected, so I assume that the shif motor is actually working.

The only problem now is that with teh BWM switch in th eon position, almost as soon as I pull away, the truck goes into 4wd and the light on th eswitch comes on. If I turn the switch off, I get 2 wheel drive immediatly.

I am assumikng (probably wrongly) that because the 4x4 and 4x4low lights on the dash flash, that there is an error somewhere, and I am guessin g that because te system thinks that ther eis enough of a speed difference immediatly i move, that it is probably one of the speed sensors that is not working. Does that sound right? If so, can anyone suggest how I establish which one? Explorers are not that common in the UK, I have asked in a few garages and no one has a diagonstic tool for one.

I guess that I need to get one from somewhere, so if anyone can tell me exacly what i need, I will check ebay, etc to find one.

Sorry this is soooo long, but I really want to get everything working.

Thanks

Ian...

 

[gijoecam]

I apologize for not catching your other post. Things have been busy for me lately. I could have saved you some work.

As you already found out, there is nothing wrong with your transfer case. The problem lies in the electronics that control the system. As you've already discovered, connecting everything causes the transfer case to lock, and disconnecting it causes the case to unlock. That tells me that, mechanically, everything is working the way it should.

Now, where to start? Without a proper diagnostic scanner (most Ford dealers should have them), it's a guessing game at best. The most likely culprit is a defective output shaft speed sensor, but without being able to monitor the two sensors, it's almost impossible to tell what the system is seeing and why the system thinks the wheels are slipping when they're not. As you've already discovered, the easiest solution is to use the brown wire mod to disable the system, but it's not going to solve the root cause of the problem.

I would suggest by looking closely at the wiring from both shaft speed sensors on the transfer case. If I remember correctly, the rear shaft speed sensor is on the top side of the rear output shaft, and the front shaft speed sensor is hidden behind the shift motor. Inspect the wiring carefully and see if there is any damage to it.

Start there and let us know what you find...

-Joe

 

[wskisoft]

Hi All,

I had a good look at teh wires and could not see any problems with them. the only thing to note was that the 3 wires that had been cut were teh 3 that go to the speed sensor ( i assume) just below the read output shaft.

I have found a ford dealer not to far away that has the scanner, but they charge 1 hour labour to do the test (ouch!!). Does anyone know where i can get eh part numbers for both sensors? I asked in the dealer, but the parts dept could not find them. I was wondering if the cost of both sensors would be less that the charge for the testing.

Thanks

Ian...