I own a 2003 F-350 SD with a 7.3. PS, this is not the problem. Intermittently the radio, power windows, and map lights quit working. I hate to admit it but slapping the dash above the radio sometimes corrects the problem. I have pulled the radio and confirmed the elec. connection to the radio is working. All three of these accessories are controlled by the same relay, I have replaced this relay and the problem persists. I am sure that I am missing a certain step in identifying the problem and need advisement.
Thank you, rynomush1

 

Leave the radio unplug and see if the others still are intermittent.

 

I will try this, Thank you!

 

Well, I disconnected the radio and the problem continued.