On board diagnostic (OBD) was designed on vehicles equipped with electronic fuel injection so you can generally retrieve the codes yourself. No need buying a scanner or running to any parts stores to check the engine light. This system is called obd1 and applies to most vehicles made before 1995 for domestics and 1993 on imports.
Ford owners can check their check engine light using the diagnostic connector located at the engine compartment by the fender near the battery. Getting the obd1 codes need a couple of tools: a 4 inch long gage 16 jumper wire and a 12 volt test light. Both tools are hooked up to the diagnostic connector and when the IGNITION KEY is turned on (without starting engine) the codes will begin to flash in the test light, not in the dash panel. If there is no code, you will normally get code 11 or 111. On Fords, there are 2 test modes, the KOEO (key on engine off) and the KOER (key on engine running). Both test modes should be used to get the accurate evaluation of the stored fault codes.
Most of the codes can be erased or cleared by disconnecting the battery negative terminal for 1 minute and reconnect. Just make sure to check your service manual in case you have electronic equipment such as radio or clock that needs reprogramming in which battery disconnection is not recommended. Finally after performing repairs on the culprit code, always go for a road test to confirm if the problem is fixed.