Which radio do you have? Does the clock display work when the ignition switch is in the "run" position? If it has a cassette player, CD player, or both built in, do those work and do they produce sound?
Also observe if the interior lights work. The radio's memory circuit is tied in with the lights. Different radio models act differently when the interior lights fuse is blown. Some will be totally dead, including the clock display. Some will play normally except the clock goes back to 12:00 every time you turn on the ignition switch. Some appear to tune but have no sound.
It would be helpful to know the radio's model number if you can get to it. It's on a paper sticker on top of the radio. The heater control faceplate has to be removed by removing four Philips screws, then the radio can be removed. It's best to not unplug the heater controller. Just let it hang by the wires. If it is unplugged, it may be necessary to go through the calibration process, and one half of that can be very frustrating and time-consuming, and it won't work if the AC system isn't working.
Wednesday, January 13th, 2021 AT 2:47 PM