Diag Code P1876??4x4 LOw /indicator flashing!!!

[4tonGT40]

My 4x4 low indicator light flashhes constantly when i turn the knob to its position..I had Ford scan the truck and they came up with a P1876 code..What the hell is P1876 The 4x4 high works fine sometimes and sometimes it flashes also.. So I noticed today while in 2 wheel drive that the front axle spins with the rear axle. While the hubs arent engaged, it should not turn while in 2 wheel. So any help/ideas would be appreciated. Electric T-cases suck. ohh yeah, when i cycle the switch on the dash i can hear what ever it is clicking in the T-case.. THX

 

[WoodBoy]

Are you sure it isnt your hubs engaging when you turn the knob on the dash. It does sound like your tcase selenoid is stuck. I think the code refers to a closed circuit failed. Check the wires and make sure you have a good ground