My 4wd is not working. Any thoughts as to where to start ?

 

I'd start by popping the front panel and tracing the gray and brown wires from the struts up to the connectors to make sure they are both plugged in. Plus you can jack the atv up with all wheels off the ground and see which wheel doesn't turn while in awd mode. Could be dirty or no fluid in one of the hubs,damage to the awd components inside the hub,etc. Plus make sure the awd light on the control switch is on. Check that the gear position switch on the transmission is operating properly. OPT

 

I know the above post is old, but I just solved a similar problem on a new-to-me 2000 325 Magnum 4x4 (Gen 4).

4WD would not engage; the AWD light on the throttle control would not illuminate. Voltage was present at the upper transmission switch and was being switched properly; voltage was present on Pin 1 at the AWD switch (Grey/White) and was being applied properly to Pin 2 (solid Grey) when the switch was in the ON position.

Turns out the problem was on the GROUND side of the circuit.

I spliced into the brown wires coming up from the hub actuators, right at the white two-pin connectors under the front cover, and I grounded the newly spliced wires to a convenient bolt nearby.

That's it. Now the lamp in the switch illuminates properly and the hubs activate as designed. All better.

 

Basically same as what some have been doing on the Sportsman 500 and other machines. The thin brown ground wires loose ground between the switches,going into speedos(if equipped) down to the hub ground wires.Grounding both wires to a stronger one wire ground solves the problem in most cases.