This is my problem I have 2004 A8L and rain water filled the floor and flooded my computers,I replaced the computers from a salvage yard ,The battery is fully charged and im getting no power to the ignition, I put key in and turn but nothing happens, no dash lights no nothing, The radio, seats trunk all work fine, The scan tool will not work , needs to be in position 1 but no power in that position, I put a test light to the plug going to the ignition switch and there is no power, only power I have is what you would normally get without having to put in the key and that is it, So putting the key in the ignition gives me nothing it will turn and then get stuck in.
All fuses are good and battery is 100%. HELP!!!!

 

Sounds like you need a new ignition cylinder.

Signs of a Bad Ignition Switch | eHow

 

I have a 2002 A6 Quattro. Replaced small power steering hose due to leak. Flushed, filled and bled system according to Bently. Now no power steering and no fluid movement. Any Help?

 

if the battery and the relays are alright, then the problems with the ignition lock cylinder. get it replaced.

 

replaced ignition still nothing, replaced ecu and power control comp. and still nothing.

 

I have replaced the part were you would put the key and still nothing.
I think have have no power to the ECU.

 

either there should be an electrical short or the parts that you bought from the salvage may be already dead. get the wiring checked, ensure wires and connections are in good condition.

 

I'm thinking that the car needs to go to Audi to have the computer and keys programmed,I took the keys from this audi and put them in my other A8 which is running with no problems and the keys did the exact same thing, they just turned and did nothing, no dash lights or anything, I no it wasn't going to start but at least the dash lights should have come on but it did nothing so I'm thinking that keys need to be programmed.