the service 4wd light came on and i took it to get looked at the shop told me it was the transfer case motor so i replaced the motor on my own in my driveway....after a u joint replacement on the front drive shaft i installed the new motor and everything went real smooth drove up on my lawn to test it and to make sure it worked and everything was fine put it back in 2wd and went to drive off for a regular 2wd test drive(just incase) and then a min after i pulled out the fuse for the 4wd (its the ats or atc fuse in the box under the hood) blew and i have no idea why i wasnt even in 4wd and i shifted in and out of 4wd properly before i left can anyone make any sense of this or has anyone had this problem????

 

was the power on? you may have blew the fuse if the key was on?

 

The motor may be drawing to much amps during the switch. You should check for a short to ground on the power wire and a short to voltage on the ground wire. Also when the service 4wd lite comes on its a Chassis code and will need to be read by a better scanner, not Autozone. Shutting off the blazer and restarting it will often clear the light. If the TCCM detects no errors at start up the light will be off. If it comes on again after a switch to 2wd or 4wd and short drive but can be cleared by turning engine on and off, It could possible only one of the three speed sensors on the TC. If you try another fuse and it blows you need to check wiring. My opinion.

 

I sure there is a thread on the TCCM here somewhere but it is also notorious for corrosion at the connections. This can cause all different problems. Pull the passenger side kick panel off and unplug the connections and look for corrosion. It worked for me when I had problems.