Nissan Repair: wiring problems on nissan 240sx 1993, nissan 240sx, relay switch

Question
My sister in law is having promlems when her ignition switch is in the on position, sometimes she has power other times she doesn't. She also sometimes experiences loss of power whilst she is actually driving. can anyone throw any light on what the problem might be. she had someone take a look at it and he changed the relay switch but the problem still exists. she does not have problems when it is in the start position if there is power there it will crank over.

Answer
Beverley,

It could be that the ignition switch itself is worn out as the car is fifteen years old.  You say the ignition switch, in the on position will allow the power to fail to all items?  If this is the case I would first check the connections at the battery, to include all the fuses and fuse links (Small wires that, when overloaded, will burn through to protect the car's electrical system) are good.  There are relays under the hood that should be checked to see if they are working properly.  If it is not the switch then it will be a loose connection or a defective relay.