Technical lights and clicking

[Green-E]

I have a 2000, 16v ELX, all day long no problems, however when the lights are switched on, shortly afterwards the orange security code light illuminates on the dash. Soon after an electrical fault kicks in which results in a regular power cut to most electrical items. The side lights flash on and off, the wipers stop and go, the gauges flick up and down etc.
A relay also clicks in the driver side fuse box but this is affected by the power cut rather than being the cause, I have removed it but the fault continues.
After a period of cooling down everything starts up again as normal, has anyone any ideas ?

 

[diamond]

Try this it might help,check your battery connections for tightness and then check all your earth connections under the bonnet,to find the earths they are on end of black wire and are bolted to engine or chassis,the main one is from battery earth-just follow its route from battery negative connector.