hi there if they are sure there is no faults in any of the computers you need to carry out a instrument panel test ,by the way this test might not work all depends on the panel,,press and hold the button on the end of the wiper stalk and then turn the ignition on and check to see if all the lights are working correctly if they are all working ok just press the button or stick on the instrument panel ,also what i would do is if you have a mate with the same car swop the panel round and se if the fault is still there, if the fault goes you now you have a panel fault ,if you find the fault is still there there must be a fault in one of the computers or there is a fault with the wiring,hope this helps .
mark
May 2008