Specific Question on Type II ACC
 

I have a very specific question on Type II ACC (Vertical pushbutton unit, Servo controller, no mono-valve) for a 1980 300D.

I've been under this dash more times than I would like to admit and I'm back to operating only after hitting defrost for a minute to close the vac interlocks and then going to auto-high. I'm pretty sure one of my vac switched is toast again.

Here's the question: I have a manual for Type III ACC (avec mono-valve) that I use alot to find things because the layout is similar. Does anyone have an image file of the Type II system vacuum and electric, specific to a 1980 300D? Also, can the pb unit be removed on this model without tearing out the whole center console?

Thanks for any and all replies.

someguyfromMaryland

Hi someguy , my system only responds if I push the defrost first and then select from there . I get functions from all selections but even to shut it off I have to push defrost and then off . I thought a vacuum leak would make the system default to defrost only . I have a manual on CD if that helps .
Yes the console has to come out to remove the push-button assembly , but it's not too hard , I did have to remove my armrest and push the seats back and recline them though , then you have enough room to slide the console back and out . I was hoping that resoldering my amplifier would cure the pushbutton problem but it didn't . Good luck .

Thanks, Kyle. I rep;aced the master vacuum switch (the green one) once and restored the system to normal where it would come on automatically once temp and vac were present, so I'm pretty sure I lost a vac switch again. I'm just trying to get a diagram of the vac system specific to the car to try and do a more thorough job this time.

someguy

The most common failure of the "servo" style A/C/C system is vacuum.
On the W123 diesels the vacuum harness(A/C) goes by the battery, & battery acid & plastic just don't mix! I would remove the battery & inspect for damage there.
Use a good rubber vacuum line for repairs.

Good advice, MBD. I've BTDT already. Tore open the black covered set or lines to find several eaten up. Patched them all, repaled an aging Int'l Diehard with a new Interstates Monster battery, and then wrapped the newly repaired lines in a spliced open coolant hose for a shield.

I know I might be facing rampant battery acid contamination, but I'm hoping for the best. The car is a beater and I'm trying to get every mile I can out of it. The ride is incredibly smooth still and I amaze friends with how smooth the 617.912 is once it's warmed up and at speed.

someguyfromMaryland