Oil pressure warning light fault

[Holydiver]

Can anyone help??? I have a fault with my T25 pickup (1.9) 1989 F Reg

I was happily driving my pickup the other day as normal and suddenly the oil warning light started to flash along with the warning buzzer, so I stopped switched off the engine and started it again all seemed fine so off I went until about 2 mins down the road and the warning light and buzzer went off again. By this time I was only a mile from home and I know the oil level was fine so I carried on home.

Once home I double checked the oil level which was fine as it had only had an oil change the month before, next I changed the oil pressure switch but still I have the fault, other then this it runs fine and I've been driving it around but I can't stand driving any longer with the buzzer going it's driving me mad.

This problem only started after I ran out of petrol as the petrol gauge is faulty can't see that there's a connection there myself.

PLEASE PLEASE does anyone have any ideas (yes I thought about braking the buzzer)

To re-cap on the fault
After about 2-3 mins of driving the oil warning light comes (flashing) on and stays on, but if I switch the engine off and back quickly whilst driving some time the light comes back on straight away, most of the time it stays off for about 2-3 mins but every now and then it stays off and that's why I thought it was a pressure switch fault.

According to the Haynes manual models fitted with a buzzer should also have a high pressure switch?? but I can't find one anywhere.

Pressure switch fitted is a grey one and connected to the yellow wire on the loom, which from what I can see is correct.

Cheers
SBBFUK

[Grun]

sbbfuk,
look here

and here

Could be electrical, 14 pin connector behind cover on instrument panel is one likely place, but to be safe, you'd better get an oil pressure check done soonest. Heavier oil grade may help, but not looking good. Other (low pressure switch) I seem to remember is down under left hand cylinder block and is wired blue/black. The switch you changed is near water pump, right?
Mike