hello all.. a mechanic friend and i have been trying to replace the mode door actuator on my 99 silverado the past two evenings after work.. he got it installed yesterday but when you put it on vent the air blows out the defrost and when you set it to blow out the defrost it blows out the vent. does anyone have any ideas on what is going wrong?? before, i guess the old actuator had "seized up" because the air would only blow from the vents.. thanks for any help in advance and have a great day...

shane