Oil Light

I took my cluster out then replaced it, but now the oil light comes on. I thought I must have done something wrong, but the wring looks okay and everything else works including the MFA.

The yellow & blue wires from the senders have continuity back to the clocks.
The oil light does the short "ignition live" flash then goes out until I start the engine.
If I start the engine, the light starts flashing (no buzzer). If I disconnect the the blue/black wire the light stops flashing.
Oil is Fuchs 10w40, filter is Mann, both have been changed fairly recently.

This is how the wires are attached:


 

Oil light flashes at low rpm or Idle, that is the senor on the head right side as you are looking at it. Blue, Green, brown sensor.

Oil light flashing and Buzzer at high RPM that is the white one on the oil filter flange.

The single pin black on the oil filter flange is the oil temp.

When you state that you took the cluster out and replaced it, was it with a different unit, or the Original.

Make and model as well as engine would be nice to know as well.  

Check the connectors and wires on the senders.

The light is controlled by the "EL" shaped board in the back of the speedo housing, they do go bad occasionally.

They all seem to be the same colour. It's the one at the back in picture that grounds when the engine is running.
Should anything ground when the engine is running?

It's the same clocks.
Mk2 16V clocks
9A 2.0L 16V
MK2 16V K-jet fueling and ignition.

The White one 1.8ar should be grounded when running and only open when the pressure drops below 1.8 bar @ 2000 rpm. Causing the oil light flash and Buzzer to squeal.  The Main control for these as stated is at the rear of the speedometer



The other is usually .3 bar and  operates open when low pressure at the head when idle.

According to the Bentley, they are only all located on the Oil Filter Flange when you have a 16V.

Okay, so the 1.8 bar (blue wire in my pic) is supposed to be grounded when the engine is running.

Grounding that wire causes the light to flash when the engine is running and also when it isn't running.

That suggests that the cluster is at fault and the engine is okay - right?

I still have the mark one clocks to test this with. Can I test with just positive, negative, and 1.8bar wire?