Oil Pressure warning light NOT working.

Hi, I have an 83 GTI converted to ABF with OE Digifant EFI. My oil pressure light does not come on at all. Oil pressure measued with a borrowed gauge and its fine. I can find plenty of threads about the oil pressure light being on all the time but none about being off!
I checked the wiring at the fusebox (CE1) and found D1 spliced to a yellow cable I believe this to be the high pressure warning. I spliced to the blue black cable but this made no difference. The blue black cable ran to a sensor atop of the oil filter housing closest to the engine block with a blue plastic surround. I measured resistance between the spade connector and hex body of the sensor and got open circuit with the engine on or off. I measured the sensor with the yellow cable and got the same results this is to the right of the oil filter top nearest the battery and has a white/clear housing.
I am not sure how the light behind the dash works, is there a way of testing it? Shorting D1 to ground did not make the light come on.
If anyone can be any help with this it would be greatly appriciated.

Regards

Woollen

D/1 goes to the 1.8 bar white oil pressure switch, which triggers the light and buzzer if oil pressure is low around 2k rpm.

for the 0.3 bar blue or brown pressure switch look for a yellow wire with a spade on it on the dash loom, run your 0.3 bar switch wire to this.

or if the engien loom is from a later car the oil temp sensor green/black will be on a spade wire on the clock loom, the 0.3 bar oil pressure switch wire is on D/21

Thanks for the reply. I was hoping for a rubjonny reply! Car is an 83 engine donor was a 97.
Just went out to the car whilst typing this, I swapped the blue/black cable onto the white sender connected the other end to D/1 and the yellow cable onto the blue sensor, connected the other end to the male spade on a yellow cable and bingo. Oil pressure light working as it should. Hoorah!!!!!!!! Massive thank you on that score.
I will try to find a home for the MFA oil temp cable green/black now D/16?

What it is earlier cars you have blue/black oil pressure switch wire to D/1,  green/black oil temp to D/21 and yellow pressure wire switch on a spade separate to the fusebox.

later cars both oil pressure switch wires go thru the fusebox D/1 and D/21, mfa green/black oil temp is on a separate spade above the fusebox.

So just need to figure out which yours is and run the wires as appropriate

D/16 is an ignition live, used on mk2 for the reverse switch