Very strange.....
It would be very unusual for two radio units to exhibit the same problem, so the problem must be elsewhere. Do you know if they checked the wiring and power supplies to the unit? Also, the headup display- could this be faulty and affecting the radio unit? I assume they programmed the new radio to the vehicle? I know when my instrument cluster was replaced by a local garage, they had to take it to Ford to get it programmed.
If the vehicle is under a warranty I would press the dealer (if it is a main Ford agent) to sort it.

 

they apparently checked everything, and after the warranty finished, i took the entire dash apart to check the wiring, pulled apart the radio and controls, and the only thing i could see was that in the radio control unit, whats protecting the circuitry board from shorting out on the metal backing is a very thin sheet of plastic, which it has gone through already...

so i added to it, to prevent it from going through... but it still did not fix the issue...

as for the power supply, where is that located?

 

By power supply, I meant the 12V feed to the unit and the earth to the chassis. These usually come in through a multipin connector on the rear of the unit. Your description of the thin insulator- was this in a separate unit to the main CD player? If it had previously shorted, it could have been that the unit was already damaged.

 

Back to the dealer........

Coverage as a continuing issue should exist, No idea here as to actual timeline involved - but with receipts and a call to Ford if needed I would HOPE for some resolution from them, as by your story it doesn't sound as if a fix was ever achieved during the orig. warranty period.

 

If there are separate controls on the steering wheel or in the back, the wiring harness could have shorts. I've seen things like this happen with HVAC systems where I work.