1980 Electrical Schematic Questions

I am putting a 302 that originally was hooked to a car with a full instrument cluster up to a car that has idiot lights. Namely, a 1980 Fairmont 2-door sedan. As you well know, these cars don't have an oil light and a temp light, they have one light with a picture of the engine on it. I intend to have gauges to monitor the engine, but I thought it would be cool to have the light work, too.

My question is this:

The (crappy Haynes) schematic shows the oil light sender as being just a normal switch, with one wire going to it. the oil light sender on the 6 cylinder engine that I took out has 3 wires on it. The plug that goes to the engine has all three wires, of course. If anyone out there has the Ford shop manual for a 1980 'Mont/Zeph, or the Electrical/Vacuum Troubleshooting Manual (EVTM), I'd appreciate any information you can help me out with.

Later,
Mike.

Mike...Took a quick look at both my Haynes & a 1979 EVTM. Like you discovered, diagrams show one wire to both the water temp and oil pressure sensors. On some sixes I've seen a lone wire going to one sensor then a simple loop to the second. When either switch closes it completes ground and the warning light comes on. Wondering if the three you have consist of wire from dash light, one to oil sender, and the last to water temp. If this is the case a meter should show all are connected together somewhere. Steve

The thing that is confusing me, is; why have two circuits in the oil pressure switch? I'm used to seeing one terminal on the oil pressure switch, and I don't really understand the need for the second one. It would make perfect sense if there were two wires on the one terminal, and they were connected in parallel to ground, but that doesn't seem to be the case. Also, since the chassis side of the engine plug has the same extra wires that the engine side has, that would mean that, if the wires come together, they do so somewhere in the wiring harness.

I'm starting to wonder if maybe this car wasn't a late '80, and it got some '81 wiring. I know that the '81s had some crazy shit going on, though.

Later,
Mike.

I see 3 wires to the oil pressure sender/switch in the 1981 and 1982 EVTM.
The wires go to a fuseable link, choke heater and the MCU module. They started using this late in 1980, according the 1980 EVTM.
It was mostly a California thing.
You can see it better in the wire diagram for 1982 on my web site.

So, since I don't have an MCU, I should be able to figure out which circuit on the oil pressure switch is the "normal" oil pressure switch, and make sure that it gets hooked up, and the light should work.

Thanks.

Mike.

before you get started, you do realise that the original "warning light" used switches that were either "on or off" senders for the idiot lights and the active guage set uses senders that have a thermistser for the temp guage and a variable resister for the oil guage.

most of the modern ford oil guages use a on/off switch for the oil guage. this means that so long as minimum oil presure is met, the oil guage always shows in the middle, thats why there is no fluctuation of the oil pressure guage.

some of the mustangs used active oil pressure guages, what type of guages are you planning on using? if you are using stock ford guages in in a stock ford dash, or aftermarket guages.

if you want the idiot light to work and have an active guage set, you may have to run both types of senders.

The long-term goal is to have a full custom dash with all Auto Meter stuff. In the short term, I was thinking of going with some cheaper stuff just to keep an eye on the engine, but have the light function as a "hey, look at the gauges, moron!" light. I'm also thinking that I should buy a couple of the Auto Meter gauges that I want, and pod-mount them temporarily, until I can afford more, then buy those, etc. The gauges that I want are full-sweep, stepper-motor driven, with built-in idiot lights. Damn, that's a lot of hyphens.

That on/off switch for the gauge thing is pretty damn stupid. I mean, if it's just gonna be on/off, then it might as well be something big and bright that screams, "I don't have oil! I don't have oil! Shut me off!", instead of something that you would actually have to look at.

Later,
Mike.

speaking from my own experiences, unless somebody gives you the gauge set at a real steal, or better yet just gives you the guages, save you money and time and put the ones that you want in right away. trust me i have plenty of crap laying aroung for cars i dont even have anymore.(wheels, intakes, radios ETC) over the years i have amassed tons of stuff that i havent gotten around to installing, luckily i have been able to get rid of most of it, but that doesnt fill in the holes that i've drilled in the car from changing stuff around.

failing puting in active gauges you can seperate the wires for the coolant and oil on the driver side fender apron. they are shorted together so if iether sender goes to ground, it will turn the the idiot light on. youl just have to run another light and substitute the brake light for one of the senders. it's easy to pick up the parking brake light switch wire.

the problem is the downtown senders are not always accurate & sometimes leak. a lot of stuff is made in china, and it pisses me off to no end that american companies like Crapa, car quest, checkers, o rileys, autozone try to sell this substandard scrap metal, yea, they may have a liftime waranty, but that only covers the sender, not your engine. its best to use the ford stuff.
if any of you guys work at these places-no offence meant, i just like my cars.

hey you know what would really be cool, use a relay on each sender to set off a tone generator or to kill the igniton. just a thought, (sorry, sometimes i think too much)

I actually thought of doing the "kill the ignition" thing, since I'm using a Crane HI-6, and there's a wire you can short to make the thing stop sending spark. I was actually thinking about hooking it up to the oil pressure light sender. That way, when you were cranking the car, it wouldn't fire up until it had oil pressure, thus reducing cold start damage. I'd probably have to put a manual switch on that circuit, though, to disable it in case it failed.

Later,
Mike.