Fan speed detected is more than 300 rpm different from targeted value for more than 60 seconds.
1. Is the fan running at full speed?
- Check 4 wire control connection to blower and control.
- Replace harness.
2. Is the fan running at a modulated speed?
- Check 4 wire control connection to blower and control.
- Replace harness.
3. Is the fan not running?
- Check the 3 wire power connection to the blower and control.
- Replace harness.
- Replace Blower.
