service engine light on speedometer and a/c not working. can`t get codes

Hello, the service engine light and the air conditioning concerns are two different problems. You'll need an OBD I compatible diagnostic tool to retrieve 3 digit trouble codes on this vehicle for the light. This will help steer you in the proper diagnostic testing direction. For the air conditioning, testing the system for refrigerant as well as proper power and activation of the compressor and related components is needed.

How to retrieve OBD 1 codes: https://www.youtube.com/watch?v=V8nZpQyoRh4