I just bought a 2006 Ranger XLT 4X4. After a rare snow in TN, last night, I tried to engage the 4wd, this morning. It did not engage. The lights on the dash do come on briefly when I start it, but when I turn the switch to either position (4 high or 4 low), no lights and no 4wd. Any thoughts or suggests for a newbie to the Ranger world?