btgt570

I need help or ideas on my heater blower problem on my 1997 ES300.
Blower motor fan stopped working, runs only on the very low speed that it constantly runs till fan speed is turned up by the fan control switch.
Fan is running slow so if it has a fuse that must be OK?
Climate Control panel lights up OK, you can hear doors in the air ducts moving when you switch from floor, to panel, to windshield for air to go, so they all work.
A/C compressor comes on so that works. I just can not get fan to come on any higher than the very low speed it runs normally.
Any ideas? Need help trying to solve this.
This must not be a common problem as I don't see any other postings with similar problem?
PLEASE ADVISE, Thanks::

esucaris1

Well I hope this helps as I own a 93 but the part should have the same name
(Power Transistor Circuit) it is located under dash above the gas pedal
CIRCUIT DESCRIPTION
The air conditioning control assembly controls the blower speed by varying the voltage at terminal BLW which
applies the base current to the power transistor.
The air conditioning control assembly also monitors the power transistor collector voltage at terminal, VM to
control blower air volume precisely.