Mystery wire harness

[CAChevy]

Anyone know what this goes too? It was just hanging loose in the engine bay. Application is 1984 C10 305 w/CA emissions.

[casper71]

looks like the low oil pressure cut out switch. Cuts power to coil when the oil pressure drops out.

[CAChevy]

I thought about that..but the old engine didn't have the sensor and there are three wires in that harness????

[casper71]

see if you can track down a wiring diagram for your year truck. PO do some silly things to these older trucks, may be reason sensor was missing. Third wire in the harness may be for the dash light for oil pressure.

[MalibuSSwagon]

Only 2 wires go to the switch. Previous owner likely removed the switch, it's usually mounted on the back of the engine with the gauge sensor. If it's a 3 wire plug, then the third wire is the low oil pressure warning light with dummy lights.

[CAChevy]

Ok...there's two blue wires into the harness and a pink...one of the blue wires that comes out goes to the electric choke..the other blue and pink go to the box on the firewall with another 50 wires into oblivion.

Why would the choke be involved with low oil pressure switch?

[Pine Bark Auto]

So that choke coil doesn't start heating up until engine is running (showing oil pressure).

[ElGracho]

Take a look at this old post:

http://67-72chevytrucks.com/vboard/s...3&postcount=11

[CAChevy]

Awesome! Thanks for the help guys!

[Axle]

That is the oil pressure power cutout to the electric choke if you do not start the truck.
The electric choke starts opening when power is applied, so if you turn the key "on" without starting it, the choke isn't going to start heating up. Unless you are in the habit of turning the key "on" without starting the truck, don't worry about it.

If you want your electric choke to work without the sensor, you jumper it as yours is.
Basically it means your engine is not original, and the threaded plug in the block is probably stuck fast and not worth the bother/risk of trying to remove it.
I live in a cold climate, bypassing mine has not negatively impacted anything.

Alex.

[CAChevy]

I went ahead and got the oil pressure switch and a new harness because this one is toast. I'll just install it on a tee with the oil pressure sending unit on the back of the block. Doubt it'll make a huge difference having it original or not but I might as well get rid of one more reason for the smog inspector to fail me on the visual.

Thanks again for the help. It's much easier to post on here and get the correct answers from those who know than to spend an hour looking for a knock sensor only to find out CA emission equipped trucks didn't have one.