4WD Drive Indicator light coming on intermittently: Help

[MAF_SURF]

Hi

I drive 97 4Runner and sometimes during driving the 4WD mode indicator lights on+flashes on the dash board without me pressing the 4WD mode button. Please help. What could be the cause of this.
If the lights comes and flashes does this mean the the vehicle is in 4WD mode.
The transmission is Auto.

Thank you