Hello all-

1997 chevy 2500 4wd gasser 140k miles- 4WD won't engage, no light, no 4WD.

Worked fine last winter, was doing my end of summer checks before winter comes in, didn't work.

Transfer case is going into low gear with 4 lo.

jacked it up, engaged 4wd, transfer case output shaft is mechanically engaged. Checked voltage at the two connectors that attach to the front axle, with the 4WD off, no voltage, with the 4WD engaged (via the lever) no voltage. Checked all fuses, they are good.

Recent work performed - did an overall tuneup, plugs, wires, map sensor, crank sensor, ignition module. Don't think this is a factor, but it is some work that was performed between when it worked and when it didn't.

Is there a relay or something else I need to check? My chilton manual isn't giving me any wiring diagrams for this.....

Any input is appreciated - thanks.