Radio not working

First of all, this was right in the middle of switching over, so does the car's plugs have two seven-pin connectors, a gray one and a black one, or a single gray connector with two rows of pins? Does the original radio have rounded corners on the face plate with a screw hole in each of the four corners, or is it a square-face radio with two mounting ears?

What is the symptom with the factory radio? Does the display light up? Do the back-lights work when the dash / tail lights are turned on? Does the car have a factory amp? It would be mounted to the floor under the passenger front seat.

What is the model number of the factory radio?

Does not matter. There is one round-face radio that cannot be repaired but there is a better factory radio that replaces it. For yours, by far the most common cause of a totally dead radio is the missing ground strap. There is no ground wire in those two connectors. There is a braided ground strap that must be bolted to the back, or there will be a small black wire that clips to one of two terminals on the back. Usually the radio will work through the outer shield of the antenna cable, but that isn't a very reliable power ground.

The next thing to look at is a lot of do-it-yourselfers think they found a ground wire in the gray plug by reading continuity to ground. In reality, one of those is reading through all of the tail and running lights on the car, so it will read very low resistance, and the other one reads the same because it is reading through all the dash lights, then to ground. The tail light circuit tells the radio to dim the display when the head lights are on. The dash lights tell the display how much to dim.

If someone tried to use one of those lighting wires for the ground on an aftermarket radio, that would have grounded that circuit through the antenna cable's ground shield and blown a fuse. If the dash lights work and the tail lights work, those fuses are okay.

Next, the first two wires in the gray plug must have 12 volts. The first one is pink and must have 12 volts all the time for the station preset and clock memory. If that is missing, some radios will work but the clock will keep resetting to "12:00". Some will work but have no sound. Some will be completely dead. That memory circuit is not labeled for the radio. It is always tied into some other circuit that is always live. In this case it is the interior lights, so check that those work.

The second wire is red. That one must have 12 volts when the ignition switch is in the "ACC" or "RUN" positions. If that is missing, look for a cut wire. It comes from the ignition switch, but there is a whole lot more stuff on that circuit, so if the switch is bad, you will have a lot more problems than the radio.

Either someone cut it off or it fell down inside the dash. You will see a threaded bolt hole in the middle of the back of the radio where the strap bolts to. You can run a new wire too, and bolt the other end to the firewall sheet metal.