A/C and alternator question 82 300SD
 

So I finally got my A/C charged and changed to 134. Air is nice and cold but for the life of me, I can't figure out how to open the middle vents without using the EC button (which lets in outside air). Cold air out the all 4 of the side vents and nothing from the middle. Normal?

Other question is now at low idle (with or without the A/C on), the alt light glows but goes out the instant I push the gas even like 1mm. Alternator on the way out? Thanks!!!

You make it sound like converting to R134a was an objective in and of itself. At best you settled for R134a :)

I don't know why the center vents work in EC but not in black arrow/white arrow mode. Seems to acquit the center vent pod in which case the PBU (push button unit) must be bad or at least need resoldering. There's a writeup on resoldering the PBU. Sometimes called CCU (climate control unit) but on early 126 ACC (automatic climate control) has a control unit outside the PBU.

Maybe the alternator is bad and you only need is a new regulator. Check that the regulator brushes aren't worn to the point of not making good contact.

Or your idle speed is too low.

Sixto
87 300D

Thanks for the input. Yes, I settled for the conversion as a compromise. I'll have to figure out the vent thing and read over the write up. I really appreciate the help!