Dear All,

I have a 2002 1.6 Ford Focus and the heater blower/aircon will not work on settings 1-3, on setting 4 the blower works but the Air Con light goes out. I have spent hours going through all of the posted help and done/checked the following:

1. Checked all fuses and relays - all fine;
2. Replaced the pollen filter, Blower Motor Resistor and Dash Switch (new parts from Ford);
3. Removed the blower motor, bench tested and checked the bearings - all fine;
4. Checked the loom between the switch and the resistor - although all of the wiring is good and the connections are good no power to the resistor from the switch on settings 1-3, there is power to the dash switch;
5. When the engine is cold the cooling fans dont come on, when the engine is at running temp both fans are on together;
6. When the engine is cold and the air con button is pressed the compressor clutch does not engage, however when the engine is at running temp the clutch engages and releases at the opperation of the dash switch in possitions 1-3;

Questions:

1. Should the Air Con light go out on switch possition 4?

2. What could the fault be? Is there anything I can check before a spend a fortune on an auto electrician - ford main dealer mechanic inspected the car for about 30mins and simply shrugged his sholders and said he had no idea what the problem could be!

Please Help

Derek (Brighton)

 

Right,

Spent an hour or so checking all of the wiring this evening to and from the switch and risistor against the wiring diagrams - all checked out fine. All point to a faulty blower resistor which is very strange as it is brand new supplied by ford main dealer on monday morning and even after first fitting the resister the blower never worked on settings 1-3 and A/C light goes out on setting 4.

On examination of the new resister - no signs of overheating, however when I checked with a multimeter I was able to conclude that there was no connection accross the component spot welded to two small terminals at the end the resistor itself, I assum this to be some sort of temp overload diode. As soon as I bypassed the doide, as a test, with the resistor connected to the car and the ignition on, the blower came to life on all settings and the A/C light was on on setting 4. After about 2 mins the whole resistor got very hot indeed although the actual terminals to the connector did not apear to get hot even after 5 mins of maintaining the short - no fuses popped.

Questions:

1. Is it really possible that the resistor sold to me by ford was faulty - anyone heard of this?

2. Is it normal that the risistor gets very hot, and was the test I did to bypass the resistor safety diode valid or even sensible?

3. When I purchase a new resistor should I check for a connection between the terminals at the end of the resistor? or is this not a valid test!

 

Answers,
1. YES, without a doubt, and it's getting much more common, not just ford but so called prestige marks like BMW also.
2. Yes it will get really hot, it turns the excess voltage into heat, when it resists it, like if Cheryl Cole was trying to rip my clothes off I'd get hot resisting her, so wouldn't ha ha!!
Bypassing the overheat diode is safe enough, so long as fuses in place, and diode is not anywhere it could do damage from heat etc.
3. You can test before fitting another resistor, but don't pay for it, yours is faulty so return it.
tabetha

 

Thanks for that, all working fine now new resistor in place and a fully functioning airconditioning - got small issue with ford who say that electrical components are not covered under warrantee! To be honest cant be bothered with an argument over £16

Went to maplins at weekend and purchased a thermal fuse for £0.89 and cut off the old one and soldered new thermal fuse to resister terminals - works fine so I now have a spare!