When I try to engage the four wheel drive on my 2008 F-250 only the 4X4 light on the dash blinks and does not engage.

Not to insult your intelligence but if you are trying to shift into 4 low you must be stopped and the transmission must be in nuetral. 4 high can be engaged while driving at any speed below 45 mph. If 4 high is what your trying to do and the light blinks it could be the solenoid on your transfer case is seized up or broken. I have had my solenoid freeze up in the winter and through repeatedly turning it off and on it broke loose and started working again.

on a side note, if you have manual 4x4 instead of the electronic switch inside, you wil need to turn the hubs from free to lock

When I switch into 4 wheel drive the light just blinks whether it's 4 high or 4 Low

Mine too 2010 f250 any ideas

The actuator may not be working properly. The blinking light tells you something is wrong.

i have a 2008 f 250 that lopes when in 4 wheel low the tracking light blinks on and off the whole time in 4 wheel low any help would be beneficial