How do you reset check engine light 1991 nissan pickup?

To reset the check engine light on a 1991 Nissan pickup, you can disconnect the negative terminal of the battery for about 10-15 minutes, which will clear the engine codes. After reconnecting, the check engine light should go off. Alternatively, you can also use an OBD-I scanner to clear the codes, if you have access to one. Make sure to address any underlying issues that triggered the light before resetting.