Gearbox
The coils are mounted to it.
The PCM is mounted right in the center above the engine.
The 1990 Chevy Celebrity engine is distributorless, the ignition is handled by a combination of the engine control module(computer) and the ignition control module. You did not mention which engine the car has. If your car has the 4 cylinder engine the ignition control module is below the intake manifold at the rear of the engine. You can follow the spark plug wires to it. The coils are mounted to the ignition control module. If your car has the V6 the ignition control module is near the starter and again you can follow the spark plug wires to it. Again the coils are mounted to the ignition control module.
The engine computer is the cruise control module. It is mounted to the passenger side firewall.
The 1998 Ford F1 50 pickup truck ABS module is mounted to the firewall in the engine compartment. The module will be on the passenger side of the firewall.
UNDER HOOD, CENTER, UPPER ENGINE AREA, MOUNTED ON TOP CENTER PASSENGER SIDE OF ENGINE
If your 89 Celebrity has the 2.5L 4 cylinder engine the ignition module is mounted on the block below the intake manifold toward the drivers side of the engine. If your 89 Celebrity has the 2.8L V6 the ignition module is mounted on the block on the radiator side of the engine on the drivers side. Both are a bit of a pain to get to, but it is doable.
yes the 2.5L 4 cyl engine has the ignition module mounted to the back of the engine block,firewall side.the crank sensor is also there under the moduel and coils
The engine computer is mounted on the right side of the firewall, inside the passenger compartment. Changing it out is not a trivial task.
on the 6 cyl it is either mounted on the distributor or on the driver side of engine compartment close to the firewall. If it is not distributor mounted it will be in the middle of a large alloy heat sink.
The ignition module on a 5.7 Chevy engine should be on top of the motor. It is mounted beside the distributor.
Looking from front of truck, it is mounted on top of the engine, left of the throttle body.