Oil Pressure warning light not illuminating

[lezmtaylor]

I have a 2002 4.4 with 94000 miles.
A fault with the oil pressure warning light : switch on ignition and I get NO op wng light on instrument cluster.
Have done the following:
Replaced op switch at base of oil filter.(it is a single wire sender)
Checked the wire from op switch to op led , have continuity.
Checked op led to earth ..OK.
Checked engine oil pressure with gauge : 20psi tickover and 60psi at 2500rpm engine hot.
Do the led's ever go bad?, how can I check the led? can I replace the led?
I obviously know how to get into the instrument cluster and split the clear plastic cover from the binnacle.
The fault is: op light NOT coming on,not illuminating when ignition is switched on.

Lez