Check the Motor on the transfer case it looks like this...
September, 29, 2008 AT 5:46 PM
Checked that part is switching fine but I still do not have 4whl dr
September, 29, 2008 AT 6:01 PM
On the front axle there's an Actuator Motor it is Vacuum Operated. Check the vacuum lines
September, 30, 2008 AT 1:01 PM
I checked the actuator motor it seems like it is gettin a full swing when I activate it but still no 4 x4
September, 30, 2008 AT 2:27 PM
Ok, are you able to raise the vehicle off the ground, all 4 wheels, safely? If so once you have it off the ground have someone inside start it hold the brake then put it in 4 wheel drive and slowly release the brake. Look under the vehicle is the front drive shaft turning? If not have person in vehicle hit the brakes put in park and turn vehicle off, Then with a vacuum gauge attach it to the actuator and apply 10 - 12 psi of vacuum. Start vehicle and put in 4 wheel drive if wheel turn then you have a vacuum leak. It is most likely a small leak just enough that the 4 wheel drive won't engage.
If the front drive shaft does not turn then the problem lies either in the transfer case motor or the transfer case itself.
September, 30, 2008 AT 10:26 PM
I don't know if 2003 f150 is set up different then a 1997 ford f150. But we recently had the same problem the dash showed it was in 4 wheel drive yet it wasn't. Took it in to mechanic and the solenoids were bad on both sides. They replaced the one solenoid and got it into 4 wheel drive but they couldn't get it to go back to 2 wheel so they had to change the other solenoid. Now it works fine.
October, 23, 2008 AT 11:32 AM
I have a 2003 f150 that did the same thing. I took it to Ford and they replaced the gear box because the 2 prongs that engage into the gears had broken off so I was getting a light telling me it was engaged but it wasn't