Below the 4WD shifter on the floor is an indicator diagram that lights up when one shifts into four-wheel drive. Actually the front and rear axle indicator diagram should light up. When the lever is in two-wheel drive the rear axle indicator should be on - it's not. I loosened and removed the rear axle light bulb but it tested good. There must be a relay or switch at or around the transfer case which might be causing the light not to come on. Any ideas?