1997 suburban 4WD fuse blows

[steve in alaska]

have a 97 4WD Suburban that blows the 4WD fuse in fusebox whenever transfer case (manual shifter on floor) is put into 4WD high..it was working fine! All other electricals seem to work OK. We had just gotten about a foot of snow, and the next day this occured. Any thoughts?
Thanx!

[777stickman]

Steve: My '98 schematics show the 4WD fuse powers the front axle actuator. My guess is that or a shorted power wire to the actuator. Disconnect the wiring at the actuator. With a good fuse in, turn the ignition switch to run and shift to 4WD. If the fuse doesn't blow, it's probably the actuator. Good luck.......Steve

[steve in alaska]

thanx Steve..
I am working on it for a friend, and I threw my neck out last night so hadn't had a chance to crawl under it yet! Armed with this info, I'll get after it. I guess the axle actuator took the place of locking/auto hubs huh?
This would make sense, though..the snow may have damaged/shorted the actuator/wiring harness. I'll give it a go, and report back. Many thanx again!
Steve

[Jeremy-WI]

I think I'd disconnect the front axle actuator and then replace the fuse, then switch it into 4x4 and see if it blows the fuse again, if it doesn't you may want to get a new actuator, especially if the actuator is made out of metal- that would indicate it is a thermal unit and are failure prone, usually the first sign of them going bad is that it takes a while for the front axle to engage(blinking 4HI light on electronic shift or no 4x4 or front axle light on manual shift). Sometime in MY 97 or 98 the switch was made from the thermal unit to a motorized, the motorized actuator has a black plastic case, it engages almost immediately, won't disengage when you turn the key off, and has 3 wires to it instead of 2 wires for the thermal(thermal has lt blue and black, motorized also has a brown wire that has 12v anytime ignition switch is on)