i have a 98 ford expedition and when i put it in A4WD the light comes on and it blinks is this normal? it stays on when i put it in 4H and 4L...can someone help? A4WD is the only one that blinks.

 

I have the same year and same problem, but mine blinks when it is in 4H. It is fine in all the other settings. Never have been able to figure out how to fix.

 

this is prob. normal i never use A4WD...

 

I have the same problem with my 97. I have done some extensive research on this problem, and have still not found an exact answer. The things that I have found out are as follows:
It could have lost program for the A4WD.... Computerized system can be accessed by Ford dealer and be reprogramed.
It may be a hall effect sensor...... There are 2 sensors on top of the transfer case, one of them could be bad. There is no way of knowing which one it is. They are about $30 Each! Once again.....Dealership can diagnose problem with computer!
It may be a motor plate out of adjustment...... Replace motor.... not sure about price, but Dealer can Diagnose problem with computer!
Lastly, it could be the selector switch, I have completely ruled this out on mine..... I pulled the switch and tested, Everything AOK! Some had an abundance of grease in them, resulting in no contact.
As you can see, most of my research has led to a trip to the dealership for diagnosis! $70 to put it on the computer and find out what is wrong with it, then if you choose to have them fix it, it would be the price of parts and labor. The parts are most likely gonna be "Dealer only" so you will have to get them there any way! Replacing them is easy, so I would do it myself, and save about $50/hr labor. I hope this has helped! I have been researching this for about 3 months, and have posted questions to about every Expedition, F-150, SUV, And Ford Tech board I could find on the web. This is all I have found, so I saved you a bunch of ground work!

 

where are the sensors? are they easy to get too and change? is the motor easy to change? and where is that exactly? the dealer said it sounds like motor....however, the 4H and the 4L works good

 

Both sensors are on the top of the transfer case. They don't really seem that easy to get to but, neither are the sparkplugs! The motor is at the rear of the transfer case, it is relatively easy to get to.

 

do you just pull out the motor and install the new one? thank you so much for the info.

 

I'm not too sure on the motor replacement procedure. I have ordered a cd rom manual for mine and it hasn't come in yet! But I have read that you have to cut the wires to it and reconnect them later. Hope this helps, but I'm not really sure.

 

i found out there are no sensors on top of the transf. case on the 98 i will try replacing the switch on the dash

 

Hey I got some more info for you! The transfer case has nothing to do with switching into A4WD! There are only three possible settings on it, 2WD, 4HI, and 4LO! the sensors are on the rear and side of the transfer case, they are held in place with one bolt, I think it's an 8mm, but don't quote me on this. Mine is doing the same thing, so I have been checking everything. I have found out that there are 2 vaccuum modules on the firewall on the passenger side of the engine compartment. When you switch from 2WD to A4WD, they click but will not engage the system. I traced these lines to a vacuum actuated switch on the front Differential. It seems to move freely, but It doesn't make any diffrence in the light. I will keep working on it and let you know how I make out! Before you go changing parts and spending a bunch of $$$$$ make sure it is actually a broken part, you could easily spend $1000 and still not have it fixed! I'll let you know as soon as I find anything out!

 

there were no sensors on the transfer case thats what the parts person at ford told me...he looked for replacement sensors for the 98...but i forgot to tell you that i moved the switch back and forth and the A4WD stayed on so i think i will try to replce it ..20 bucks my price....i have these settings on this switch..2W,A4WD,4H,4L....

 

I has the same type problem with mine, and it was the 4wd dash switch. Pull the switch and take it apart. (It opens up easy, just be careful of the small spring and ball inside.) You wil see a ton of grease, and dirty contcacts. Clean this crap out, clean the contacts with some cleaner, and re-lube with white lithium grease sparingly. Should fix it........................

 

I FIXED IT!!! before you go start getting into things i went to ford and i got a new switch it is very very easy to replace and it only cost me 35 bucks alot better if i was to take it into a shop , they would have chg. me a lot

 

Good deal Tommy! I'll have to check continuity on the switch and see if it's my problem too. I have already pulled it apart and checked contacts, they are clean, but still no A4WD. I'll keep trying and let ya'all know how I make out!

 

If you pull the switch and check continuity, but you may not find anything. The switch works with different level resistors inside to switch between modes. You may have continuity, but the switch will still be bad. If I remember right, there are 4 wires on the switch, I think 2 are for the light inside, the rest control the trans. case. I hope you fix it...............