I read in my Catalina's owner's manual that it came equipped from the factory with a 10-pin connector under the hood for the dealer to hook up to and aid in diagnosing problems with the car. I found this little feature to be very intriguing, as it seems to have foreshadowed the everything-computerized cars we have today. What would technicians back then have been able to find out through this port? Practically everything that's electronically controlled nowadays is mechanical in the car. Here's a picture of the connector and where it is in the engine bay. The car is a 1979, and that series of model years began in 1977, which would put it probably 10 years ahead of OBDI technology.
try tracing the wires to where they go.
It might just be a breakout for the ignition system, alternator windings etc. Those are the only electrics I can think of on those old cars.
Or maybe it's some kind of aftermarket lighting connector?
I could do try that and see where they go. I could also look in the service manual wiring diagrams. I doubt it's something aftermarket, this car is practically bone stock, other than an aftermarket stereo w/ a CD player and a now-missing subwoofer. The car was originally purchased by an older person and lived in the garage for most of its youth. It was sold to a guy my old lady's dad knew, who put an aftermarket subwoofer in. The car got impounded and he wanted stuff out of the trunk. He was going through a divorce, so he made a deal with my old lady's dad that he'd pay the $500 impound fee and the guy would transfer the title. It was done, and the guy came back a couple months later and sold the stuff he wanted out of the car for more cash. Lol. The car only had around 70k on it in 2013. Her dad put around 30k miles on it, then stopped driving it. I bought it during quarantine for $750 as a project and plan on keeping it as stock as possible.
It probably brings out electrical signals from various parts of the car such as the electronic ignition, alternator, etc. to be analyzed by proprietary test equipment. The AMC Eagles I used to own had a similar diagnostic connector under the hood though I never tried to make use of it.
I figured you might have an idea on what that is, with your knowledge of little-known facts on old cars 😀 I wonder if such a machine could still be found somewhere. I wouldn't mind playing with something like that, just to see how it worked. That's how I end up getting myself into most of these car projects, I'm an endless tinkerer, infinitely curious and always learning to fix things.
I believe I found what you were looking for, I believe it was called the "GM Connection".
The connector was for a machine like this or possibly a later model like the ST-210. They are, of course, collectors items now. Scotty's Dad might have had one in their corner Texaco gas station. I remember seeing them and thinking it would take a genius to operate one. Some machines had an oscilloscope display for the guys with a PhD. https://vintageautomobileadvertising.name/2017/05/vintage-gm-ac-delco-st-200-diagnostic-tune-up-center-gas-station-retro-display/
You might like this low quality video.
May be @scottykilmer will be kind enough to elaborate?
I searched for: 1979 pontiac obd connector diagnostic port
Apparently, GM cars (millions of them) had this port between 1977 and 1980.
The information you are looking for starts on page 35:
Interesting stuff! I have a multimeter I could use to see what that stuff does, lol. I expected it to be done exotic machine, as the article states
Yes, I was surprised the technology had started that long ago. I think it's also great the old Pontiac is still going. I only wish more of those old GM's from the 70s were still around.
I've heard they were really popular as demolition derby cars by the late 90s and 2000s, and many 70s GM cars ended their lives that way, unfortunately. I don't remember seeing them, but I was 10 or thereabouts. The relative lack of cars makes it a chore to find broken pieces to replace mine with. My B-billar trim panel is broken and I want to replace it while I replace my headliner, but I can't find any. I'm not a GM fan, I prefer Ford, but I've always liked the Pontiac brand. GM knew how to make solid cars back in the day.
My Dads 77 Catalina had one.
