Cadillac STS Forum - 2005 through 2012 Discussion, 05 STS with clicking/popping sound in dash in Past Cadillac Vehicle Discussion; Originally Posted by Midnight
There are actuators that control the air doors. They have a layer of resistive material that ...
There are actuators that control the air doors. They have a layer of resistive material that over time wears off. When it eventually wears through, it can cause them to click, as they move until the worn out part, and then think they need to move back, so they move back, onto the good part, repeating. Sometimes they get lucky and move through it to the intended position, then the clicking stops for awhile. I imagine once it starts to fail, it deteriorates rapidly with all the movement.
Here's a picture of the inside of my failing actuator module. You can see it's worn all the way through in spots:
They are like $40 a piece and kind of a bitch to install (at least my passenger side one was) because it's up inside the dash, I had to do the thing where you sit upside down in the seat, getting too old for that kinda maneuver And there was a screw that was hard to access. I have yet to do the driver's side one so maybe it's easier.
Here's a picture taken looking "up" into the guts behind the dash on the passenger side. You can see the module in the center with the wires going into it.
Anyway, if you hear clicking (I thought mine was the CD drive seeking) that seems to be coming from the dash, this could be the issue. Unfortunately, adding lube on them (even if you could, they are well sealed) wouldn't help at least in my case, you can see they still have a lot of grease, but it's already worn through so replacement is about the only fix.
The drivers side is beyond tough to get to. The drivers side is the one that controls the temp. setting. Mine stays around 75 even though the display changes when I'm in ac mode, when I change it to heat I get full control and the clicking stops. Lol one day I'll change it out
I just did the driver's side. It's hard for me to say which was harder. For the passenger I had to sit inverted in the seat (with head where your feet usually go) but once there, and with a stubby enough screwdriver (I took a stubby and cut about 3/4 inch off the handle to make it super stubby and used a small neo magnet to keep the screws seated), it was easy enough. Have to take the glove box out. I could do again in 15-20 min or so if I wanted to hurry, now that I know where everything is.
Driver's side, you have to move the seat back all the way, move the steering up all the way, kind of enter the floor area face-down and twist around so you're facing mostly up -- not recommended if you have a bad back. There's about the same amount of room to work. You'll want your super stubby screwdriver for the upper screw. You can hook your right arm around the back of the brake pedal to get good access to that area. You will have to operate on the upper screw by feel only.
I had to re-do the passenger because I actually installed the wrong side there. The passenger's "lever" part is slightly longer, but the driver's side one fits there. I noticed it when the other one, being too long, didn't fit. So the second time doing the passenger side was much easier, mostly owing to having a better tool. So just be warned that those actuators have the same body, and make sure you're installing the correct one if you're doing both!
Hopefully this is helpful to someone
This is a better view of the passenger side one:
This is the driver side one:
This is a comparison of the two. Identical except for length of the lever part. Passenger (longer one) on the left, driver (shorter one) on the right:
Finally got around to looking at mine today. There are two actuators on each side. The upper one is bad on both sides of mine. On Rockauto they list 6 different acdelco actuators. Does anyone know the part numbers would be for the Top one on each side? The number that is written on them does not match the numbers on rockauto. Top one on the passenger side ends in 8580 on my car. Passenger side one shown above is the lower one and ends in 8590.