I have 89 RS TBI with a 305. The fuel pump relay harness has been cut off by the previous owner. I have a 91 harness and relay but the wires are missing. Does anyone know what colors match up? The 89 wires coming from the car are solid red, solid purple, black with red stripe, and green with white stripe, and tan with white stripe. The solid red and solid purple are thicker gauge wires than the others. The 91 harness has a solid red wire coresponding to (A) on the harness (thick wire) solid black (F) thin wire, solid purple (E) thick wire, and solid orange (D) thin wire.
the 89 GM#14089936 the 91 GM#14103304

 

Go to this link GM-ECM drawings . All the info you need is there.