my heater fan is stuck on low.is this a bad relay? how doi checkit?
fan motor on 1997 Lexus ES300
If the fan comes on at all, then the realy is good. The fan speed is controlled by a transistorized controller (called a "linear controller") which is controlled by the A/C control assembly. The diagnostics are not really simple and would require a good understanding of these types of systems and good diagnostic/ repair info. Generally this would be a job for a technicain with good diagnostic skills.