There is nothing much you can do to a malfunctioning t/stat other than replace it if the reset procedure failed. If the fan on switch works on this then I can tell you how to change the wiring temporarily so you can operate the furnace by the fan on switch if you cannot obtain a new t/stat.
If you need instruction manual and operational manual for white rodgers thermostat 1f90-371.
Then click the link below :---
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Thanks.