My 1988 Olds has a connection under the dash for what I think would be an OBD I diagnostic tool. (I don’t have the owner’s manual to check, but one is on order.) The “service engine light soon” is on, but the car has been serviced thoroughly and regularly and runs great. Will an OBD I device reset the light, and if so, where to find one of these? Any information relating to this topic is appreciated. Thanks for your time
This is called the Assembly Line Diagnostic Link. If you look close, you’ll see an A and B terminal. Using a paperclip or something simular, jump between these two terminals and turn the ignition to the run position so that the dash lights come on. The Check Engine light will start to flash out codes.
The first code it will flash will be a code 12. And will repeat three times. This means the computer is in the diagnostic mode. And will appear as -. Where = a flash and a -= a pause. After this code has been displayed the real trouble codes follow. So for example if there’s a code 36 it will appear as ***-**. Get these codes and then it can be determined as to why the Check Engine light is on. Then once that’s fixed the codes can be erased by disconnecting the negative battery cable.