I have a 1996 dodge 2500 v10 4x4 i just replaced all the vacume lines for the 4 wheel drive because all of the other ones had broken, i noticed after testing the 4x4 it is now not coming out of 4 wheel drive i pulled the switch off down by the axle and come to find out that only the black line is pulling vacume and not the red one any suggestion on what i should do