I have a 1999 Expedition. We had a snow storm I've had to put it in 4WD on occassion. Now that all the snow is gone, I put the switch back in AWD. the 4x4 light goes off, but its still in 4WD. any suggestions??

it should automatically kick in to AWD once abs sensors sense wheels are slipping, or on some model there is a eletric switch you turn or press to engage AWD

no near stated,now that does makes this IMPOSSIBLE just that.
no 4wd system stated.
which one?

on mine, 04 , you must never drive on dry pavement in 4wd
its part time 4wd not AWD
do you have AWD.
if car is fitted with PT 4wd, , then drive to dirt, or grass or ice or snow
and put car back in 2wd.
or risk winding up the driveline and damaging it.

starting in 2004 this system is an option, got this knob?
http://www.fixkick.com/tranny/xfr-case/4wd%20windup/suzuki-grand-vitara-4mode-4wd-selector-switch.jpg

yes? or no, we can not guess this, it must be stated.
or read the operators guide now and see all those warnings there.
see the LOCK word, that too means stay off of dry pavement.

-Possibly time to replace new one.


Mai

There is a small difference in what you are saying here. "AWD" stands for All Wheel Drive. 1999 Ford Expedition is equipped with (A4WD) which stands for Automatic 4-Wheel Drive. There is a big difference between these two systems. The AWD has no driver controls and drives all of the wheels all of the time. the A4WD system ia capable of shifting in and out of 4WD automatically as needed, depending on wheel speed sensor data that indicates wheel slippage. The A4WD also has a 4WD Mode switch mounted on the instruent panel to allow the driver to override how the system operates.

FIRST, check to make sure that the 4WD Mode switch is in the "AUTO" position. If the switch is in the correct position, then you will need to scan your transmission and transfer case control modules and perform visual an functional inspection of the system to pinpoint the cause of the malfunction. It could be anything as simple as a defective mode switch to a major problem like bent/broken shifting forks inside the transfer case, requiring complete overhaul. Proper diagnosis will be required.

This is very strange because of How the low range is engaged. I drive a 1999 F150 4x4 which has the same dash and controls for the 4x4 as your Expedition. I do know that the fan control switch is unfortunately the same shape and very close to the 4x4 switch. It is easy to grab the wrong knob and turn the wrong thing than was intended.

My initial impression is if it is possible, your girl could have reached over to move the fan switch and actual grabbed the 4x4 switch instead. Or you were warming up the Expedition and meant to turn up the fan and instead turned the 4x4 switch to Low. Or a backpack she was moving with schoolbooks could have hit the switch. What puzzles me is that to go into Low range, you need a foot on the Brake and simultaneously need the gearshift in Neutral and the 4x4 selector in Low. That is 3 things to make the low range happen.

Even if your foot was on the Brake and the sensors caught the gearshift going through Neutral on its travel to Park, the 4x4 Selector would have to be in Low. There is one problem you can have with the 4x4 Selector.***The Selector has 3 Resistors and a LED bulb.***

You stated the Selector switch was good. This would mean there were 3 different Voltages under the vehicle. Sometimes when the LED bulb burns out, it shifts the Voltage out of range for the Servo, and although the Selector says one thing, the Voltage at the Servo has the wrong value for that function. Since the dash light and the Servo agree on Low, it would seem the Selector is out of sync with the other 2 parts.

I hope my solution is very helpful in solving your problem.

hey well i have similar problem on my 2000 awd, it seems to get stuck on 4 all the time. when i turn it grinds and thumps like heck. anybody knows how to go about this prob?

there are 2 systems.
one is a part time system only.the 4x4 locks and is for ice mud and snow.Driving full time will damage the transfer case.The other system is a full time system and the selector says 2wd,4wd part time ,4wd full time and 4 lo. if in full time,it can be driven all the time even on dry roads.The full time is really an all wheel drive system.
the 4low is a very low gear and the main shifter has to be put in neutral and then the transfer case put in 4 low.attempting to put it in 4 low while in "drive" will make a gear grinding noise.
getting out of 4 low is the opposite.shifter to neutral and then put it in 2wd and then in drive.The newer durango has an electronic transfer case with a dial on the dash.The 2002 was available with 2wd,4wd,awd and 4 lo on a switch.The 1999 has the lever on the floor .

if its awd then you never need to switch to 4wd as you always drive in AWD. if its selectable there will either be a shift lever or push button to engage it. 4wd kills some fuel economy. use it where traction is bad - ice- rocks- mud- sand- snow- dirt. some 4wd will become unstable in some circumstances as well. be careful.

Do you have a check engine light? When it wouldn't start, was it cranking over? Sounds like it could be a transmission range switch.

Hello
I had this with a C3500 4x4 it was the wiring contection at the transmission please test all these problems as ths may be a cheap fix.

Hope this helps
www.limotec.co.uk
Regards Paul