UK Car Repair: heater fan problem, electronic speed controllers, fan speed controller

Question
2001 Vauxhall Astra, 1.6 Club Estate. Automatic. My fan heater developed a intermittent fault and I had traced the fault to a loose connection. After trying remove the fan motor to assess the connection. I found that I couldn't improve the connection. I replaced the motor to find that the fan will only work on fan speed 4.


Answer
When blower motors are concerned, the automotive establishment has been moving into the realm of electronic speed controllers for heating and air conditioning since 1998 and fewer and fewer cars are using the tried and true resistor system. The problem is that sometime you will have one and other times not. See if you can find the resistor and take it from there. If you cannot find one, go through the wiring again and clean the switch contacts. If no improvement is made, you may want to find another fan speed controller at a recycling center. If it has an electronic one it will be built into the backside of the control unit in the dash. One other thing, turn the switch on to setting one and gently pull out on the knob. See if that brings it back to life. If so, go get a new switch. You could clean it, but you would be doing it every 3 months to keep it going. Once the terminals have started to corrode it will start to overheat and give the car a strong plastic melting smell followed by a lack of heater motor speeds once again.

Regards,


John