radiator cooling fan not working

[8bahead]

here it is short and sweet. checked fuses replaced relay have continuity in harness. to fan out hooked to battery and it works any ideas thanks. its a 1990

[Jmrec100]

probably something like the temp sending unit. I have a 1999 and first time it was a bad sending unit. Problem has returned and I am checking everything again. I haven't overheated YET but ^&%$ close. Seems the fan comes on only with the AC on or when the gauge reads near overheating. I suspect either a bad sending unit AGAIN in mine or a bad ground or temp gauge. Other than these annoyances, I do like my Cavalier. Just wish it was less annoying problems like my old Toyota was.... I sold my Toy with 270,000 miles and still running. I treated it badly. I treat my Cavalier like a baby because of the miles I drive, I change my oil every month, or 3000 miles....But these annoying issues like bad fuel gauge and fan switch or fan not turning on except with AC on...