whining noise when driving, interior lights flash on/off on 2003 Ford Windstar

The car makes a horrible whining noise. It seems like it happens after the car heats up.
The interior lights flash on and off at random times. It has been nicknamed "the disco car". No mechanic has been able to find the problem (including the dealer site).

Asked by for the 2003 Ford Windstar
Where is the whining noise coming from? Does it occur only when the vehicle is moving? Does the noise change with engine or vehicle speed?
Hmmm...well, it seems like it happens when the car has warmed up. It definitely happens when accelerating and is louder when turning . I don't think I hear it when the car is on but stopped. It is very loud and can be heard outside of the car.
1 more answer
The interior lights randomly coming on and off is caused by the switch in the ingnition cylinder lock that senses the presence of the ignition key. Try squirting some silicon spray lube into the ignition key lock cylinder and then insert the key and work key in and out of the lock multiple times.

The whining noise is probably the power steering pump. It may be low on fluid.