"Service 4WD" comes on then using A4WD, 2003 Envoy. 4-Hi works well, no codes..

[Creamer1]

Okay.

Truck: 2003 GMC Envoy
4.2L I6, Vortec 4200

Problem: When using A4WD, seems to be in 2WD ?? and SERVICE 4WD light comes on. WHEN THAT HAPPENS, it won't de-select into anything else (the dash switch.) WHEN SHUT OFF, Service 4WD light goes off and it WILL select into anything, including 4-Hi.. then pulls like a train, since 4-Hi WORKS and WORKS WELL! And no codes.

Thanks, "Bomb Cyclone..."

Am I pulling Fuse #8 and putting it back in when I get home ???