The flat faced electronically tuned radios all had the same electrical connectors and pinouts from years 1984 through 2000. There is a gray connector and black connector. Each had 7 pins.
Wiring diagrams show no connection to a PCI bus. I believe that came in mdoel year 2001 (curved face radio) and communicated with the IPM / intelligent power module which was an add on to the PDC / power distribution center in year 2001. IPM was not installed in years prior to 2001.
The radio requires proper grouonds to function as ground is NOT provided through the 2 electrical connectors. When mounted in the dash originally there was a braided ground strap between the chassis and the instrument panel. Is the antenna jack firmly seated in its receptacle?
Since it is a used radio it would have station presets set internally. Those radios did not lose station presets when power was removed. With all electrical connections and ground made and a suitable anttenna connected, power up the radio and press the scan button. The radio should march through ascending frequencies and find a station that plays. Try both AM and FM. Maybe the radio is good but the display has a bad connection and is not powering up so you can see the frequency and time?
Attached is a wiring diagram that show electrical connector pinouts and connection for an amplifier. Separate image shows the attachment of the braided ground strap in the dash. Ignition key switched power travels through fuse #8 in the junction block to pin #6. Unswitched power on pin #7 is provided by the BCM / body control module. Through model year 2000 the factory service manual makes no mention of an anti-theft feature in the radio.
