74 super Oil pressure dummy light staying on when disconnected

[misanthrope222001]

Hi, I have a sudden issue with my oil pressure dummy light in the gauge cluster. It has been working properly ( going off once the engine has started ) and then suddenly it just stays on. I checked it by pulling the wire connection from the sending unit under the distributor, but the light in the gauge just stays on. From what I've read, the light should turn off when I pull this wire. Also, the e-brake light at the dash comes on and off intermittently suddenly as well. It does this with no regularity or predictable reason. I have noticed that the ebrake light will sometimes go on/off doing nothing more than slamming the drivers side door. Should I assume there is a short somewhere? Is my logic sound in coming to this conclusion? If so, where should I even start to try and figure out where the short is, or what is causing this issue? Any help / advice is very much appreciated in advance. Thanks!

[rockerarm]

Hello and WELCOME.
Your initial diagnostics of removing the wire at the sending unit and the light still being on indicates a short to ground within that circuit.
Look at the oil pressure switch wire where it exits the wire harness wrapping and look for any sign of a melted wire, as I have seen the black term #15 coil wire short to ground and melt other wires.
Sounds like your car is a '73 or later. I do recall that if a low oil pressure condition happens the brake warning lite would also light up. And this was on in-molested cars back in the early-mid 1970's.
You may wish to unplug the connector to the seat belt/brake warning lite assy and see if the oil press lite goes off.
If you are going to be driving this car during your diagnostics you may wish to install a wire from the oil press dash bulb to the sending unit so as not to impede the operation of a functioning warning lite til you are able to resolve the concern.
Hope this helps, Bill.

[busdaddy]

I thought the brake warning light was tied into the charge light as a self test feature, sure you don't have the bulbs in the wrong holes?, what color is the wire to the bulb on the back of the speedo?
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[rockerarm]

Hi. You could be correct on the different circuit as it is tied into the charging circuit. I just seem to recall finishing up an oil change on a '73 and later type 1 and on initial start up viewing both oil and brake warning lite flicker at the same time.
At any rate at least the owner now knows another circuit may be related to the initial concern.
Thanks, stand corrected if wrong or misled owner.
Bill

[misanthrope222001]

rockerarm - So your suggestion worked! I unplugged the seat belt / e-brake light indicator and the oil pressure light started functioning as normal. Started the car, and it went off after a few couple of seconds. Turned her off, put the ignition in the on position, unplugged the wire at the oil sender, the light went off. Plugged it back into the sender and it came back on. I much prefer to be able to see that my oil pressure is ok, than to see the e-brake / seat belt light since those can be easily visually confirmed without it. Thanks for the help!

[rayvwbug]

Sounds like you have a short to ground in that seat belt bulb or socket.

[68IHscout]

[rockerarm]

Yeah, thank you both for the feed back. I can rationalize if this was a 30+ year old car with an unknown maintenance history but my recognition were cars still under warranty. Wiring can influence some to not want to get involved.
The main point is that we understand the "stupid " electrical relationship this circuit was involved with.
Bill.