Putting the finishing touches on the engine rebuild in my '64 PV 544.

The wire for the oil pressure warning in the dash has me a bit confused.

The wire on the engine side is missing, so I figured I'd just run a new wire for it. The switch should pull to ground when there is no oil pressure and turn the light on, as I understand it.

I tried splicing a fresh wire into the dash light and nothing happened. I tapped into the wire going into the center of the bulb holder as it looked like it would be the right one.

I know an actual oil pressure gauge is better than the warning light, but I'd still like to make the light work just the same. If someone can help me figure this out, I'd be grateful.

Thanks, as always.
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http://dylans544.blogspot.com

Have you confirmed that the bulb inside is good/working?

Did youcheck the sender is earthed when stopped? Teflon tape will stop it earthing in the threads.

Yes. Replaced the bulb and confirmed with a meter that both bulbs were fine.
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http://dylans544.blogspot.com

Dylan;

Planetman has it right of course...the socket for lamp should be isolated from chassis and have two wires...one supplies Ign power, the other runs off to Sender...when sender has no pressure to open contact, it closes circuit to chassis, applying V across lamp. So it sounds like you should be looking for a second wire in the Instrument panel harness. Refer to Wiring Diag for color codes.

Good Hunting!

You've checked the oil pressure switch too? Should be continuity between the male connector and the brass body.

How many wires are attached to the socket? There should be 2 wires.
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com

There are two wires.

Does anyone know off hand which wire pulls to ground and which wire is the positive side for the bulb? My meter was no help in this matter; I couldn't find 12+ no matter where I probed. (Fuses are all good, and as best I can tell there aren't any broken wires under the dash...)
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http://dylans544.blogspot.com

Dylan;

High side is supplied by IGN+12, so Ign Sw must be in ON...otherwise, you can get color codes of wires from Wiring Diagram.

Good Hunting