1991 Plymouth Acclaim Where is the main computer system co

I hope by now you still own the car. If you have already fixed it, good, if not, the relay is a type of control, this relay(2) is controlled by the computer, it operates fuel, and engine ignition using two relays, as long as it see's, cam, crank, and has power, ground, and is ok, internally. I've replaced a few, but it's almost never the engine computer, usually its a sensor or wiring problem, and an old car may lose its crank or cam because the timing belt breaks. A 4 cylinder is slightly diff. But the belt could be broken, after you have it all set for repair, let me know. If you need any help. OK? All the relays are front left side in engine comp. Inner fender, strut, both shutdown and fuel. Fan, compressor, starter. Power for fuel, green and black. Power for shutdown, blue.