Just posted a useful link in Vintage RE: ACC operation manual. I just read this manual and read about 250 posts from archives with no help.

I have a 1978 US version 116 with ACC. I recently bought a used servo with the aluminum body; mine had a cracked body and leaked when it was cold outside.

I can get heat and I can get AC. The blower works in DEF always, as you expect. The blower works Auto HI and AUTO LO, but ONLY when the AC compresor switch is on.

I have also read the w-116 garage handbook website page for ACC troubleshooting (without test equipment).

Most ACC posts I have read deal with no fan at any button selection. I can live with this since I can get heat and AC, but I am wondering how to get fan-boosted air without the compressor being activated.

All the flaps, vents, etc. seem to work as they should. This is my 3rd servo in ten years with the car and I am hoping the aluminum body will be good for more than a couple of seasons.

I had the exact same problem on the Blue Whale and George Murphy said it was probably the amplifier.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Thanks

I'll investigate that. Is the amp what people sometimes fix by re-soldering or is that something else like the cruise amp?

Like I said, I am better off than most, since all the important stuff works and I can live with it this way.

There might be one other thing going on. One of the vacuum elements with a switch that moves the flaps might be failing in the non-AC position, but is OK in the AC position. I think the flaps have to be right before the blower wiil come on, and they are in different positions when the AC is on.

Who knows? It's too complex for me.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Yeah, there's a lot going on in servoland. Maybe if I just wait until Jupiter aligns with Mars. I appreciate the help as to where to start looking.

Okay then.
I'm on to the vacuum elements trail. A new amp didn't change anything. I am open to any other ideas.
Thanks for the help in the past.