oil light on - off- on off plus temp gauge not consistant - please help?

Hi, I have a 2000 4.0 hse. recently the little book came on every now and again on the heater. then the temp gauge on the dash stopped working or became inconsistant. Then the oil light came on!!!
The oil is fine and seem to pump ok. have replaced the oil pressure sensor as well as the coolant temp sensor. Both work sometimes. engine is operating just fine. but light still comes on every now and again. temp gauge works every now and again.
the heater is only blowing warm on passanger side..

any ideas or is this just random land rover electric faults

Please help if you can

Ok, today we have a fully working rangie. I'm very happy today!! - Oh the oil light came back on but only flickering?!?