[stackj]

O2,

I am speaking from a 337B, but this may well apply to the O2 as well.

When hydraulic pressure is applied to the system, the landing gear doors are either forced open or closed.

Let's put the gear handle up. First, hydraulic pressure is applied to the landing gear door actuators. The pressure is applied in the OPEN direction as the Landing gear door solenoid is not actuated.

When all three gear are up, power is applied from the bus, through the nose gear up switch, then the right main gear up switch and finally the left gear up switch to a switch on the power pack. With the gear handle in the UP position, this switch then applies power to the Landing gear door solenoid, causing hydraulic pressure to be applied to the doors in the CLOSE direction. Looks like this function is working OK for you.

Now let's put the gear handle down. First, hudraulic pressure is applied to the landing gear door actuators. The pressure is again applied in the OPEN direction as the Landing gear door solenoid is not actuated.

When all three gear are down, power is applied from the bus, through the nose gear down switch, then the right main gear down switch and finally the left gear down switch to the same switch on the power pack. With the gear handle in the DOWN position, this switch then applies power to the Landing gear door solenoid, causing hydraulic pressure to be applied to the doors in the CLOSE direction.

This is apparently not happening for you. The most likely cause is that one of these four switches is not functioning correctly or a wire is broken somewhere in this circuit.

Be very careful. Position of all these switches is critical! If you find a broken wire, you can usually repair it without moving a switch. If a switch has failed, MAKE SURE YOUR MECHANIC IS FAMILIAR WITH YOUR GEAR SYSTEM BEFORE ALLOWING HIM/HER TO MOVE OR REPLACE A SWITCH.