On my 1990 Sierra 2500 the four wheel drive fuse blows ,i've disconnected the diff. accuator and transfer case switch and it still blows the fuse so i ruled those items out.hope someone can help or i going to run a separate wire to the switch to power the accuator.

On my 1990 Sierra 2500 the four wheel drive fuse blows ,i've disconnected the diff. accuator and transfer case switch and it still blows the fuse so i ruled those items out.hope someone can help or i going to run a separate wire to the switch to power the accuator.

I have a set of the factory manuals for 1990. I will take a look tonight and post what I find.

//2000CAYukon

Looking at the wiring diagram, you need to check the transfer case relay (drivers side firewall), front axle solenoid switch (factory manuals has it front of engine near diff case) and 4wd indicator lamp. The all share the same fuse.

//2000CAYukon