2003 F150 4 wheel drive doesn't work
My 2003 F150 will not go into 4 wheel drive. It has the switch on the dash board to go into 4H or 4L. It has never had any problems and never made any noise. The 4WD lights on the dash do not display either. I checked the fuses and they are fine. I pulled the dash apart and see that there is power going to the switch. I used a meter (to the best of my ability) to make an attempt to see if the switch works. There are 4 wires that go to the switch. The 1st is red/blue, 2nd and 3rd are blue and the 4th is black. The 1st has power, the second has power, 3rd no power and I believe the 4th is a ground. When I plug the switch in and turn the switch to 4H, the 1st wire still has power, 2nd wire the power drops about half way, 3rd wire still no power. When I switch it to 4L, the 1st wire has power, 2nd has a little less power than on 4H, 3rd never had any power. Can anyone tell me if this means that this switch is bad? Help!!!!!!!