Originally Posted by mjr46
I believe one of the main differences is the location of the fuel pump relay changed from under the seat to out under the hood, so harness is different
Some other differences also.
87-88 has no airbag connectors, no mass air connector
89 has no airbag connectors, has a mass air connector.
90 has mass air, airbags, and you need to look where the harness connects to the headlight/alternator harness, has a grays and black connector.
91-92 has mass air, airbag, only one relay by the mass air connector (A/C wide open throttle), and has brown headlight / alternator plugs.
92-93 has mass air, airbag, TWO relays by the mass air plug (A/C wide open throttle and the fuel pump relay), and has the same headlight / alternator plugs (only difference being the fuel pump relay).