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Pix Request, "Oil Filter Switch"

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theleisure

theleisure

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Pix Request, "Oil Filter Switch"

Hi guys,

My oil pressure warning light has a new bad habit. For some reason it is staying on after I turn the key <span style="font-style: italic">off</span>. This should be an easy fix from the looks of the wiring diagram. It looks like a Green goes from lamp to fuel gauge, a White/brown goes from lamp to "Oil Filter Switch", and "OFS" goes to ground.

Here's my request-- can somebody please post photos of the Oil Filter Switch and its local connections. I think I'll find my problem there (once I know where the switch is and what it looks like that is!)

Thanks in advance...

sean
 
Re: Pix Request, "Oil Filter Switch"

Hey Sean, Are you sure the oil sensor is not faulty and showing that you are low or out of oil?
 
Re: Pix Request, "Oil Filter Switch"

It only turns on when the car is off and the key is out... I'll go check it again now. Right now it's a reminder for me to turn the battery cut off before I go inside for the night.

I guess I'm really lazy to not just go out there and follow the wires. I'm pretty sure the switch is on a T where the oil pressure line attaches but I don't remember seeing a ground wire there. I'll post a picture and ask for comments after I go check the oil level!

**edit**

oil level is fine, here's a photo of the switch
 
Re: Pix Request, "Oil Filter Switch"

The ground is the switch body itself contacting the engine parts. There is no separate wire.
 
Re: Pix Request, "Oil Filter Switch"

Ok, I traced the white brown wire and it looks like it goes to a push-button starter solenoid in the engine bay.

At this point I'm lost. Why would it be set up this way? What would the indicator light be indicating? Is it acting correctly, lighting when key is off, for a light that's wired like this?
 
Re: Pix Request, "Oil Filter Switch"

Depending on where it is connected to the solenoid, the white/brown wire could be hot with the key off. I'm not wure how it gets a ground through the green though. Are you sure it is connected right? If it is then it would also be at 12 volts with the key on, cancelling the voltage across the light and turning it off. Some tinkering about with an ohmmeter could disclose how that green becomes a ground with power off. Anyway, the W/N definately goes to the O.P. switch. Do that and see if everything doesn't start working right.
 
Re: Pix Request, "Oil Filter Switch"

Alright Bayless! thanks for your help. I got some good news & some bad news when I moved the w/n wire to the oil switch. Now the light is definitely related to the oil pressure. However, it seems to light up to indicate adequate pressure instead of the other way around. Am I correct to assume that when I go to start the car I should have 2 lights lit on the dash-- ignition light and oil pressure light. Both should go off as their separate processes progress. My oil light is now off to start and lights up when the motor gets going. Oil pressure indicates 70 cold, 45-50 warm and my oil level is fine. Is it a bad switch?

Sean

This thread's title was a pretty poor choice.
 
Re: Pix Request, "Oil Filter Switch"

I don't think a bad switch but maybe a wrong switch. Thats exactly the behavior you would expect from a safety switch to cut off an electric fuel pump when the engine stops. Pull the wire and check the switch for continuity to ground with the key off. A good switch should be closed, zero ohms, with engine not running. Also, due to that funny behavior before, check where the green wire goes.
 
Re: Pix Request, "Oil Filter Switch"

Hey, the problem is solved. Here's a reply Peter C. of lever-arm damper fame posted on another forum:

"It's not actually an oil pressure light as we think of them in other cars. It is an "oil filter light" unique to some Spridgets. The switch is on the oil filter housing, and is meant to power the lamp when there is pressure due to a blockage in the oil filter. It is sort of a oil pressure differential switch. You are meant to change your filter when the light is lit, in case you haven't recently.

It's a good idea, with poor results. Most people disconnect it, as it is misinterpreted, and/or it gives false information. What often happens is when the engine leans as you rev it, the switch miraculously grounds and causes the light to come on.

Trust your gauge, or even have the gauge independently tested, and ignore the light. Or use it as the former owner did, or for a fog light indicator, or something.

Peter c."
 
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