MyBlue72

First off, let me start out by saying, I am new to the site and am no mechanic. Bear with me.
I'm hoping you folks can skool me on this vacuum switch / sensor. I am trying to get everything working properly on my 72 Cutlass Supreme that I bought earlier this year. Ive had a guy working on it, and he has been a bit shady to say the least. My Cutlass is a 350, automatic, with a/c. The a/c is only blowing on to the floor. This gentleman working on my car is telling me that the a/c is vacuum operated and can't operate properly (blow out the upper vents) unless I replace this switch/sensor which has a broken/missing port. It is a 3-port switch/sensor.
Question:
1) Does this sensor work the vacuum operations on the a/c?
2) What do the other two ports operate?
3) I read these sensors cost an arm and a leg. Is there a way to get the a/c blowing out of the top vents instead of on the floor without buying a new sensor?
4) Can anyone recommend a good classic car mechanic in the Asheville, NC area? (Laughing, but not really)
Thanks for any and all help,
Doug

Fun71

That sensor has nothing to do with the AC - it is an emission control device that restricts vacuum advance to the distributor until the transmission is in third gear.
You can read about it here and decide if you want to keep it connected or not. I would opt for not as I don't like things that detract from performance:
https://classicoldsmobile.com/forums...ol-switch.html

The symptom of air blowing on the floorboards is indicative of a disconnected vacuum line from the vacuum reservoir on the firewall. There should be two vacuum hoses connected to it: one goes through the firewall to the AC control switch and the other one connects to a vacuum nipple on the intake manifold behind the carburetor.

https://classicoldsmobile.com/forums...-canister.html

MyBlue72

Kenneth,
Thanks for the quick reply. I can't thank you enough. I will check out the two links you attached. The guy that has been working on it and "restoring" it has caused me so much grief you can't imagine. I am looking forward to finally getting the Cutlass to my house tomorrow. I want it out of his shop.
Thank you so much for your help.
-Doug-

joe_padavano

Start by buying an original Chassis Service Manual for your car. Originals are available on ebay. This Transmission Controlled Spark system and everything else on the car will be described in detail and servicing information provided. Don't waste your time with reprints or CD copies. There are no digital originals, so all of these are scans of a paper copy. Detail gets lost in these scans.

MyBlue72

Thank you for the info Joe. I just bought an original Chassis Manual and Body By Fisher manual on Ebay for a decent price. I like pictures.

CRUZN 66

Here are a few photos of the AC/Heater vacuum diagrams for your 72... Hope these help until your manuals arrive...

rocketraider

See you're in Asheville area. Contact the Smoky Mountain Olds Club. They're good guys and might be able to put you on to someone who understands your car and can help rather than hinder you. www.oldsmobileclub.org/about/chapters/ for their contact info.

MyBlue72

Thanks John. I'm out in Calif on vacation. Looking forward to getting back home to check things out.
-Doug-

MyBlue72

Thank you. I will check that out. Definitely need some experienced help on my Cutlass.