1995 Mustang 5.0L with AC
I don’t think my two speed fan is running on the low speed. When I am in traffic my car is getting to hot. I have checked a couple of times and the fan is not running. If I turn on the AC the fan will run and the car runs cool. Both the temperature gauge and Speedo work, so both senders should be good.

It is my understanding that the low speed fan should be running when the engine is over 220 degrees and the speed is less than 45 MPH. How do I diagnose this?

Bad Fan?
Bad Fan Controller on the radiator?
Bad block to chassis ground?
Bad PCM?
Blown fuse?