Hello again: Have a 1993 Volvo 240 wagon. 185,000. miles. Auto Transm. B230F engine.

I’m still having difficulty with this oil pressure light problem (see previous posts below).

At the wiring harness connector (inside car, above passanger floorboard, where the fuel pump relay is) I cut the oil pressure sensor wire (terminal #17, black wire) on the connector and the light went off.

However, when I jumpered a wire from this point on the connector back directly to the oil pressure sensor (effectivly replacing and bypassing the bad wire) I still have a problem.

Something is not right.

With this jumper in place, with the ignition on, all the dashlights should light up. They all come on except for the oil pressure light.

Then after you start the car, the oil pressure light should stay on for about a second.

It does not. It never lights.

Any other suggestion would be appreciated.

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posted by Cliff Pope on Fri Jan 21 03:47 EST 2005

That's it Don, spot on. I had exactly that on my 93. The alternator cable was corroding, it got hot, melted the insulation, shorted through to the oil sender wire.

The alternator cable is of course live all the time, which is why the light came on even with the ignition off.

It is worth sorting out all the wiring there, and then re-routing it so that it isn't trapped behind the engine mounting.

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posted by Don Foster on Thu Jan 20 15:41 EST 2005

I'd bet a cold one that the oil pressure wire is shorting to the alternator wire where they come together behind the alternator or where the harness loops under the front pulley.

An older 240 would probably have a failing engine harness. Yours is newer and might have suffered a crushed or pinched harness, which could have punctured the insulation. (But I don't know how this would happen....)

Don Foster (near Cape Cod, MA)

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posted by Mr. Tool on Thu Jan 20 09:08 EST 2005

Hello all: I have a 1993 Volvo 240 wagon. 185,000. miles. Auto Transm. B230F engine.

I’m having a strange electrical problem.

When the car is shut off. No key in the ignition, the red oil pressure light on the dash is glowing.

When I turn the ignition on (not cranking) all the dash lights come on (as they should) except for the oil pressure light.

I have done the following so far:

1. Removed the fuse block strip, removed all the fuses, cleaned them, and cleaned all the connectors (fuse and spade terminals), front and back, and put dielectric grease on all the fuse connections and spade terminals and re-installed.

2. Cleaned the connector at the oil pressure sensor on the engine block.

3. I believe all my ground connections are good, because I cleaned and dielectric greased all of them about 2-3 years ago.

One symptom recently (about 4 days ago) was a burning smell coming from the heat duct. I believe the large resistor on my blower motor is going bad.

Also, as weird as this sounds a weird buzzing noise intermittently came from behind the IP panel at that same time.

This occurred off and on for a day, and then stopped.

Even after these symptoms, it wasn’t until yesterday that the oil pressure light trouble started.

If you have any suggestions I would appreciate it.....Thanks...Mr. Tool.

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Mr. Tool