No 4WD high on 05 Sierra 2500

schrizo

Hello. I have a 05gmc sierra2500 6L. my rear wheel drives works great and so does the 4L. I get nothing when I use my floor shifter to put it in 4H. I get no light on the dash in 4H either but I get it in 4L. Please help me figure this out. This is no trouble code light on either. Thanks.

larryb1963

there is a relay for the 4WD . there is also a switch on the shift linkage on the trans could be something as simple as a fuse I'm assuming you checked .