My 1999 Mazda Miata MX-5 engine overheats if I run the a/c while driving at highway speeds. No problems at highway speed without a/c. No problems in town with a/c.
Answer: Your car has two cooling fans mounted to the radiator. One comes on to cool the engine in stop and go traffic the second fan turns on when the air conditioning is on. This fan is protected by a 30 Amp fuse marked fan and is controlled by a relay in the engine compartment near the driver’s front shock tower. Check the 30 Amp fuse first.