Nissan Repair: 03 Pathfinder, dot3, dash light

Question
The 4wd dash light in on on my wife's Pathfinder LE. Now when you put the selector switch to the auto position 4wd is engaged, but before it would only go into 4wd when the vehicle needed it. I have tested the relays, which are fine, so I am wondering what controls the automatic 4wd system and is that the best place to start trouble shooting?

Answer
Aaron,

The ABS system sees when the vehicle is slipping.  Either you have a defective sensor or the brake fluid needs to be flushed.  I would flush the brake fluid first.  Use Ford High Performance Brake Fluid.  You have to buy it from a Ford dealer and ask for it by what I have written or they give you the regular DOT3.  It is DOT3 but twice as high a boiliing point and makes the brakes feel excellent.