Hello Does anybody knows if the heater fan can operated manually all the time. Mine is working but sometimes it is like another control takes over and and can't get the fan to zero but from 50-100% regulation works fine. Is it possible another part raises the minimum speed. Or i have just a bad contact of course.But then why is the fan working from 50-100% ? I must say i changed the transistors by more powerful types and it could be the input impedance is to high and the input on pin 6 starts to float. Could also be the case. Grts Patrick
See the diagram below. The pin 5 is connected to an output from temp sensor which, I believe, is for automatic fan speed control. Your temp sensor might be bad. You can test by unplugging the small connector and connecting, with a piece of wire, only the pin 6. Image Unavailable, Please Login
Hello M The sensor is just a PTC or NTC i think. They work or don't work. Not intermittent as my problem. I wonder why the temp sensor is there; to protect the the regulator ( as the air from the fan is also used to cool the regulator ) or some sort automatic fan/temp regulation of the cockpit. I should have the schematic from the ecu to see this. I will start with measuring the signal on pin 5 and 6. Maybe a bad GND on pin 4. The problem is also very strange. The fan regulation is at 50% all the time the first 4 bars and then from bar 5-8 the regulation ( fan speed) works. When i start the car and the fan is set to 1 bar the fan blows very low ( a should be ) but after 1 minute the speed increases to +- 50% . 1 bar or 4 bars, all the same. PS : Did you ever measure the signal on pin 5 ( temp sensor) ? Grts Patrick
