replacing center ac vent in 92 500sl
 

i search the boards for but i couldn't find exactly what i was looking for. i am replacing the center vent on a 92 500sl. do i have to remove the whole dash? what is the easiest way? I know that there are 4 screws holding the dashboard down, 1 on each side by the door and 2 in the cluster area. Are there anymore and where? one more problem- the temperature gauge on the ac control pabel is jumpiong up and down and can't hold steady. i tried turning it up and down and it still won't hold steady. it would fluctuate a few degrees up and down. what is this indicative of? i have had this car sitting still for 2 years. i wonder if the heat has gotten to the car because it is having all sorts of problems. i am in texas where it gets really hot. it's been sitting in my garage. thanks for any help i can get.