I have a BVM F-86 (63") that I bought used. I have made 10 flights or so but none for about 2.5 months or so. Landing gear and doors have worked fine during those 10 flights. Yesterday I got it out in anticipation of going flying and my nose gear door is not working correctly. When the gear goes up all gear doors close as they should. When the gear come down the mains close but the nose gear door does not close, just stays wide open. Seems to me that it most likely is NOT getting the signal to close (when the gear is down). I do not know enough about how these gear work to know what gives it the signal to close the door. I assumed that it gets sent the signal to close when the nose gear or ALL gear are in the down position. I figured this was done by a current reading increase that is sensed when the gear reach the down and locked mechanical limit. With that in mind I reasoned that my nose gear unit currentely installed in the plane is not seeing or sending an electric current draw increase and that is why my door is not closing. I happen to have spare nose retract so I plugged it in instead with no help. Nose door still wide open with gear down. I have a call in to Down and Locked but in the mean time thought I would post here and see if anybody knows what triggers the signal to the doors to close ? Thanks