To replace an ignition control module, disconnect the vehicle's battery cables. Locate the module, disconnect wires and remove screws and parts obstructing access, tracking their locations. Remove the old module and insert the new one in exactly the same place, reattaching all screws, wires and parts and reconnecting battery cables.
The ignition module is usually located near the distributor housing or on the firewall or wheel-well. Before starting this project, check the service manual and rule out problems that are related to the module but not caused by it. Have a mechanic test the module or test the module yourself using a light timing sensor. Connect the sensor to the vehicle battery's positive terminal. A blinking light indicates that the ignition module is good, a constant light or no light at all indicate the need for a replacement.
Symptoms of a failing ignition module, such as overheating, trouble starting, engine stalling or sputtering, mirror problems with the battery, ignition coil, fuel line or spark plugs. Something as simple as salt or dirt in areas surrounding the ignition module may cause a short in the ignition system. Check for loose, worn or twisted wires, and adjust the spark plug timing to manufacturer's specifications.