You could try to fix it instead of turning off the warning light. As others said, there's a FAQ and in it is a great explanation of what you actually have, which is OBD1. This does not use a scan tool like OBD2.
You read blinking codes on the black box in the engine compartment, which steer you to possible causes of your issue. I take it the light was not on before the head job, so something changed. Did you do the work, or a shop? If a shop, it may be on them to restore correct running. But then they may not know enough about these now older cars.
If you leave the condition that is causing the light to come on, you may end up damaging the motor and your new head work.