oil pressure switch, wiring help needed! Options

[mobymutt]

I just swapped out my 1.8L for a 1.7L (so I could rebuild the 1.8L), and I can't find the wire that goes to the pressure switch.

I've got carbs, so the wire harnesses have a zillion unused wires. But I thought there would be a wire with a dangling connector somewhere nearby... apparently not.

The car is a '74. From the wiring diagram, it looks like the wire should be green with red stripes, but I can't find that either.

Can anybody tell me how I might go about finding the correct wire to hook up? Maybe the physical location of the wire run to start? Or where it comes from, or what other wires it would be with?

Any help is appreciated, thank you!

[76-914]

IIRC, that wire is attached to the rear of the engine case and goes towards the right side then stops close to the edge of the engine case.The connecting wire is below the battery and may have a plastic cover over the female spade.

[iankarr]

I'm away from the garage, but pretty sure oil pressure switch wire is part of the ignition harness, which connects via the large plug on the relay board. The oil temp wire sprouts from the main harness near the battery tray.

[Dave_Darling]

I believe that Ian has the right answer here.

--DD

[GregAmy]

Gents, my notes indicate the OP switch wire is green/red and comes from the T12-1 pin on the relay plate (mine's a '74.)

If you were standing over the relay plate from the rear, the T12 plug is the 12-pin connector on the lower right, and the -1 pin is its upper left pin.

Edit, actually a picture is worth a thousand of something...

[mobymutt]

914world to the rescue again! Thank you everyone!

Found the relevant wire wrapped under layers of extremely old black tape. This tells me a couple of things:
-the PO's mechanic didn't concern himself with irrelevancies like oil pressure
-the current owner was too daft to notice that it had never been hooked up before.

So I now have new pretty green light on my dash when I turn the power on!

With the engine running, should that green light turn off, or stay on?

[IronHillRestorations]

With the engine running, should that green light turn off, or stay on?

The light should go off.

[930cabman]

914world to the rescue again! Thank you everyone!

Found the relevant wire wrapped under layers of extremely old black tape. This tells me a couple of things:
-the PO's mechanic didn't concern himself with irrelevancies like oil pressure
-the current owner was too daft to notice that it had never been hooked up before.

PO might qualify in the DAPO category, you have to wonder about some of this stuff

So I now have new pretty green light on my dash when I turn the power on!

With the engine running, should that green light turn off, or stay on?

[76-914]

I'm away from the garage, but pretty sure oil pressure switch wire is part of the ignition harness, which connects via the large plug on the relay board. The oil temp wire sprouts from the main harness near the battery tray.

You're right. I was thinking Oil Temp. (IMG:style_emoticons/default/headbang.gif)

[iankarr]

914world to the rescue again! Thank you everyone!

Found the relevant wire wrapped under layers of extremely old black tape. This tells me a couple of things:
-the PO's mechanic didn't concern himself with irrelevancies like oil pressure
-the current owner was too daft to notice that it had never been hooked up before.

So I now have new pretty green light on my dash when I turn the power on!

With the engine running, should that green light turn off, or stay on?

Great that you're on the road to restoring things back to stock. it's entirely possible that the PO had an aftermarket oil pressure gauge installed and didn't use the stock wiring. A lot can happen in 50 years (IMG:style_emoticons/default/wink.gif). The green light should be on until the engine starts running, then turn off...assuming you have good oil pressure. If the light stays on, and your engine hasn't seized, the sender is probably bad.