Oil Light Always On ('82 Rabbit with '90 1.6L TD)

[BlackTieTD]

I've never once had an oil pressure problem with this setup in about 3 or 4 years since its been in the car. Normally, the oil light is on in the dash, start car, oil light goes out.

The last time I drove the car, I started it, but the oil light didn't go out. What happens is its bright when the ignition is turned to on, but not cranked over, then for about a second while cranking it over the light goes out completely, then it comes back on about 50% brightness and remains on the entire time regardless of what's going on (idle, driving, reved up, etc). It is a constant light, no flashing, and no buzzer.

There are no other signs of problem. Engine sounds and performs as usual, coolant temperature is not higher than normal.

I'm assuming bad sensor, wiring, or control unit.

Anyone have a problem like this before? Thanks.

[BlackTieTD]

More Info: When I unplug the wire from the oil pressure sensor on the oil filter flange, the light goes out. Plug it back in, light comes back on (with engine running). So I found the same sensor on a spare engine and put it in hoping that it was just a faulty sensor at this location (black sensor). No change. I doubt both sensors are bad.

[BlackTieTD]

Fixed: Was just a bad relay  :mrgreen:

Thanks anyway guys enjoy the long weekend.

[Smokey Eddy]

For search purposes:

many parts stores will sell you an oil filter that doesnt meet the spezifications of our litte diesels. our 1.6s and 1.9s sometimes run at decently high pressure (2 bar?) and i've heard of cheaply made filters balooning, breaking ect. I bought a "puralator" filter for about 3 times the price of a Mann or Bosch and it messes with the oil pressure and i get a buzzer and flashing oil light when the pressure is too low under a certain RPM. It also doesn't filter to the right number of microns. Mann and Bosch are the way to go.

[BlackTieTD]

Mahle is ok too.

FYI: The Bosch ones that have been made in the USA for the past year or two are CRAP compared to the genuine German Bosch filters. Cut them both open and see for yourself