Chevrolet Repair: service four wheel drive light just came on, chevy silverado, southeast alaska

Question
2000 chevy silverado
yesterday i switch into four wheel drive and when i went to switch it back to 2 hi it wouldnt let me and then the service four wheel drive light came on then this morning it switched right away to 2 hi i just took it for a drive and it was switching from 2 hi to four wheel high  with no problems  untill i got home now when i press the 2 hi button nothing happens  right now it is in four high . there are no leaks under the truck allright i just went out to get the mileage on the truck which is 84000 and it switched into 2 high but won't go into 4 high now  thank you for your time any help would be much appreicated as i am in a little town in southeast alaska and just to get to a dealer is going to cost me a 600 dollar ferry ticket plus the repairs  is it going to hurt my truck to drive it with the service four wheel drive light on thanks again

joe

Answer
The service Four wheel drive light is to alert the operator the system is not being read properly by the ECU.  If the ECU loses contact with or position of the Transfer case actuator motor the service light will come on.  Same thing goes for the front diff actuator.
 The system is drivable if the light is on as long as it isn't caught in 4low.  I wouldn't drive it around in 4low.

w