Run up on a couple of pictures the other day of the front panel and bottom of the A/C & heater controls for a factory installed system. Noticed something a little bit strange in that the various connections did not match what's in the FSM for a 75 280Z. I dug out a spare vacuum control valve (P/N: 27031-N3110)...(which is the later valve according to the fiche)...and it matched up exactly with the picture in regards to the connections as far as layout goes. According to the 75 FSM the connections are laid out in a slightly different way??

Wondering if anyone can confirm this by a visual of the vacuum control valve you might have on hand...(assuming you have it out of your car of course) () should be the same from late 74 thru 78...prior to that it was a slightly different number according to the fiche (59-1) P/N: 27031-N3100 (up to 11/74)

Pictures uploaded are with the changes made to show how it's actually laid out on the vacuum control valve.

Just one of those... "hmm...that's very interresting...but why is it different type questions"

webdawg1

Don't have one to look at but, according the both the microfiche and the Nissan Fast program, in the 'ICA' column, there is no interchangability. My take on that is, having seen both FSMs and all 74-78 factory AC systems, is that Nissan carried over the illistrations from the 74 260Z FSM to the 75 280Z FSM because the 76-78 FSM illustrations match your picture #2. You know, the kind of stuff that has 78 owners looking for the EFI main relay under the driver's side dash:)