For those of you who have done it... Now I join you in saying I can fix my own climate control.

Three issues with my 1984 W123 (278k miles). First was no center vent actuation. As expected, this was the center vent vacuum pod having a ripped diaphram. About 3 hours of work and $32 in parts and that works again.

I took the easy route and removed the glove box and center vents, working with one hand through the left vent and one through the glove box. Left the base of the pod in place, just removed the top via the four plastic clips. Getting it out wasn't too bad. Took about 30 minutes to get the vacuum element seated properly though! If you don't have a Miti-vac or other source of vacuum, don't even attempt this job.

Best hint I can add to the already posted directions on how to go about this is to get the diaphram over the top (pink) portion before trying to seat it on the lower section. Else it tends to get pinched inwards and doesn't seal (this ate up 25 minutes of frustration). Got this done by attaching the linkage to the vent flap, then jamming said vent open with a screwdriver handle in the right opening. Compressed the spring between the flap-held piston and the pink top, and worked the rubber over the top flange. Then once that was on (checked with a pump on the miti-vac) I slipped it into the base and clicked down.

Oh, and that portion is all done blind. Fun.

Second issue was poor temperature control. The foam hose which feeds the thermistor in the center of the dash was missing... Went to Home Depot and for $1.68 got a section of foam hose for keeping 5/8" pipes insulated. Now I have temperature control again.

Third issue was the fan would only go on if you set the system in defrost mode first. Turned out to be the motor itself- brushes were all worn out. Figured I would just put new brushes on it til I saw the commutator eaten down by the brush holders. Can't even take the motor frame apart to turn it down on the lathe, the case is swedged to the endcaps. For $86 I bought a new fan and didn't worry about it.