Did you remove the radio head and see if it is plugged in? On the '91 there are 2 components to the radio. The radio head that you see in the dash where you turn it on and set the radio station. Behind the dash to the left (drivers side direction) between the instrument panel and the radio is the amplifier/receiver unit. Another PITA to remove and put back in. Quite likely that is what is failing to work and not the radio head unit. I had to extract mine and have it repaired. I believe the radio head gets power from the amp/receiver unit. The antenna plugs into the amp/receiver.

The service manual tells how to remove and put back in the amplifier/receiver.

There is a power antenna relay on the relay panel. The owners manual should have the diagram. The relay panel is attached to the fuse block panel under the dash on the driver side on the firewall behind the parking brake.

Dear gawd don't pull the relay panel out because you will hate yourself. It is one PITA to put back in.

Right off hand I don't have that relay panel diagram.

 

The amplifier/receiver looks like this. The antenna lead wire is the black wire on the lower right side.

 

Thanks. I have removed the radio head unit, but had to stop before digging deeper into the dash for the amplifier. I’m hoping that it is unplugged but I find it hard to believe the previous owner would have done that, especially with so few miles. I know electronics the issue isn’t miles but time so the amplifier may be toast from age not use. I have the service manual on order.

Thanks for the quick response and look forward to being able to contribute in the future on this board.

 

Delco didn't use the best components. I used M & R Electronics located in MI to do the repair and I had them add a pigtail aux jack connection for a MP3 player. They tested my radio head and it was okay. I was getting power but the sound was horrible.