interlock valve 36 it also should be noted that the latch can be on the cab and a fixed striker positioned on the door when desired the sensor arrangement can be selected to sense a door closed but not fully latched position the door position could be one where it was known that the door was not going to interfere with or be in the way of the lift arm movement fig9 and 10 show a modified form of the invention schematically a latch plate 76 that mounts onto a door 78 is shown in latched position with latch dogs 80 a striker cylinder or bar 82 is held in the latch dogs the striker bar is mounted onto a fixed cab frame wall 84 in this form of the invention the striker bar 82 has a flange 88 that carries locating pins 90 that are not symmetrical about the axis of the striker bar and which will fit in provided receptacles 92 in the cab frame wall to make sure that the positioning of the magnet 94 is correct for alignment with a hall effect sensor 96 that is supported on the latch housing 98 the magnet 94 as shown in fig9 is inserted into a cross hole or bore 100 in the striker bar hole 100 is of size to receive the magnet 94 a smaller diameter cross bore 102 is provided in.