Resolved 2G Oil Pressure Switch and Warning Light Wiring

[msisto]

Was trying to reconnect my oil pressure switch because the wires came loose at some point and were torn off on the road. I spliced the switch wire to the green wire (yellow?) below (not the one next to the word "ground"). I realize now that this isn't the right spot and I have the proper connector for the oil pressure switch.

My question is, where does that yellow/green wire actually go (the one with the zip tie on it)? it was cut, so I have no idea where it is supposed to be. Does it just get spliced with the switch wire to connect to the warning light? I read somewhere that they were supposed to be connected, but I'm not sure and can't find an exact answer.

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[Black95TSIawd]

That doesn't look like the OEM switch.

 

[msisto]

There used to be an after market gauge that I removed a while back. Perhaps it's related to that? The oem switch with the little stud on it is there, just not in the picture. That's what I'm going to connect the gauge to. But I'm wondering what should go in place of the wire with the zip tie. Where is that supposed to go?

 

[1GAWD87]

definitely not an OEM switch. i would recommend finding one single wire OEM part. there should be three wires in that general area. blue is your switch. yellow is your power steering. white it's the dummy light

any identification on the switch?

 

[msisto]

I'll see if I can take it out later as it's hard to see. Spend so much time undoing other people's s***

 

[1GAWD87]

our cars are getting old. have you tried using a multimeter? also very common that coolant hose will swell up and leak, trim it back and re clamp it while in there

 

[msisto]

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Someone please help me. What the hell is going on down here?! Why is the yellow sender there in the first place? Found out it is definitely aftermarket. Been trying to connect oil sender to the switch, but it keeps reading max oil pressure

 

[steve]

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[msisto]

Thanks Steve. So the warning light and pressure gauge should just be connect together, correct?

 

[steve]

Nope, each has it's own wire, check your FSM. Since your aftermarket gauge is gone it's sensor is just to stop the leaking.

 

[msisto]

Nope, each has it's own wire, check your FSM. Since your aftermarket gauge is gone it's sensor is just to stop the leaking.

okay got it. Wiring is all good but the gauge still reads max. I’m guessing it’s grounded somewhere but I can’t find it. Tried tracing the wires but I didn’t see anything. Whether the sender is plugged in or not, it still reads max. I think at least in an emergency the switch will go off, which is the most important, but it’d be nice to see the gauge work again. Any thoughts besides being grounded somewhere?

Edit: Wanted to mention that the gauge reads max oil pressure even with the car off...

 

[msisto]

Okay, update for anyone interested:

I investigated the wiring and determined that it is most likely in good shape, so I figured the last thing in the line must be the gauge itself. I removed the gauge cluster and then took out the small oil pressure and turbo gauge.

The first thing I did was manually reset the needle from it's pegged position back to zero. This ended up helping later.

The oil pressure gauge seems to work with a bimetallic spring shaped kind of like the uppercase Greek letter Pi (I know, weird but it's all I could think of). Should have taken a picture but it's back in the car now. There is a coil wrapped around it and as it heats up, it flexes the spring and moves the needle.

I took a 12V power source and connected an old potentiometer to it. There are only two connections for the coil, and I attached the positive from the power source to the connection which is closest to the "L" part of the gauge. Adjusting the potentiometer moved the needle, so the gauge in fact was working.

Putting it back in the car with the needle reset, I realized that when I pressed the gas, the needle would move, but not too much further past the bottom. I know that I have the proper amount of oil, so I have finally determined that the diaphragm in the pressure sender must be bad. It was a long route to find that answer, but I learned a lot about how the system works.

I'll update once I've replaced the gauge and things (hopefully) work.

 

[msisto]

Okay, got the new sender in. That was the final problem. Everything works great now.
If anyone is curious, you should take that old pressure gauge out and try applying power to it. It's pretty cool to see how it works!