Hey Everyone,
So I own a 99 F250 Super Duty that has the electric shift on the fly system. Well two months ago it stopped working and I have taken it to the Ford dealer to be fix both were a failure to say the least. They replaced the gem module the 1st go around. Then they replaced the hubs, the 4X4 switch, and still no luck. I have tracked down all the wires, fuses, relays that are shown in my trucks manual and they're good to go. When I turn the key on the 4X4 and low range lights up.
I am running out of ideas or solutions and was wondering if there was anyone out there who knows of an answer or has had the same problem as this. let me know if there is a special relay or something I could have missed or whatever needs to be done. Thanks for the much needed help

 

okay
As you may know already their are alot of components to have this system work!
1)Fuses27,59,33,45,31,34
2)2 relays
3) 1solenoid
4)gem module
5) abs module(and all input sensors to it)
6)brake sw
7)dtr sw on trans(neutral safety)
8)shift motor on transfer case (which also has position sw inside)
9)sw on dash
10) lights in dash
11)Front hubs and vacuum pulse to lock and unlock

The most common causes is a fuse or shift motor pos sw,or front hub vacuum seals
sounds like you have a shift motor problem internal short or it is misaligned or adjusted switches.
But too diagnos this system you really need a manual.

Give us the procedure in which you attempt to go in to 4wh ?
Give use the same to into 4lo.
Results that happen in both .Any noise from transfercase any lights

A quick un mechanic test is to tap on the shift motor with a hammer and see if it shifts. they get stuck if not used often.
Rich

 

Hunter,
Do you hear the sliding/switching sound of the servo motor at all?

 

Would you like a simple, free fix?

 

A bigger Hammer CWB!!!!!!

get a manual transfercase! I don't know cwb ! WHATS THE FIX?

Rich

 

Sell auto hubs + $200
Install Warn Premium manuals -$200
Total outlay=$0.00

It has been my experience that the vacuum junk is often the problem.

 

I agree ! but we need to find out what his problem is first. right!

Rich

 

Oh............................sorry. Have you checked to see if the driveshaft spins?

 

hey guys,
well i have tried many things to get the truck to shift into 4x4.
1) started the truck and turned the switch to 4 high nothing not a single sound
2) then I tried low range but I 1st put it in netural and still the same resualtsof no sounds or lights.
3) I went out and put the hubs in the lock position and drove down the road at about 15mph with the windows down and tired to shift into 4 high, still nothing.
4) I tried going in reverse nothing.
5) I went to a gravel pit and tried seeing if the front wheels will turn just in chase 4 high or low was working by breaking the wheels loose results were that only the back ones turned no matter what I did.
The lights on the dash do work becuase the flash on when I first start but then goes out.
6) I see the front drive shaft turning but only when the hubs are locked manually

Now can someone tell me were the fuse # 45 is located at in addition with the two other relays. In my owners manual the relays are numbered #40 but don't show were they are.

 

Fuse 45 is in the lower right hand corner facing the fuse box while being in the truck.
k378 relay and k379 relay are under the hood on the drivers side fenderwell in the aux relay box.

you chk all fuse to be good ? first

you know you have to be in neutral ,foot on brake, not rolling at all, then shift to 4lo. this is where dtr,abs,brake sw,sw on dash ,shift relay379 ,shift motor .
(gem module)

4hi is the following sw on dash ,shift relay 378,shift motor ,(gem module)
Rich

 

Rich,
Thanks for the update on the location of the relay. I'll check that and see were that gets me.
Hunter