Do you have the electronic transfer case? I had this happen with my old truck and they had to replace the switch in the dash. The lights in the switch would start flashing and then the Service 4WD light would come on. If I keyed OFF and waited 30 seconds the light would stay off when I re-started the truck. Replacing the switch fixed my problem.my service flashes for about 30 seconds and goes off anyone have any ideas what this could be?this happens when i first start the truck up.
the truck shifts smooth and does not seem to have any noticeable problems.
I had a similar problem with my 04. The Service 4WD light in the DIC would come on then go off after a few minutes (or if I restarted the truck). The dealer checked the computer for DTC's and the front 4-wheel drive acuator was throwing errors, so they replaced it. On my drive home from the dealer the Service 4WD light came on again. I went back to the dealer and they had their lead technician look at the truck. It turned out that there was a service bulletin for this problem. They fixed the problem by installing the latest version of software on the trucks computer. It has been 15k miles and no Service 4WD light.