Blower settings

[Stevesixty7]

Hey guys, hope someone can help. I went out in the car earlier and all was fine with the blowers on all settings. Came out of the shop and noticed that the blowers were not working on settings 1, 2 and 3 but 4 works fine. Could this be a fuse? Any help greatly appreciated.

[eddie eastwood]

usually the blower rheostat needs replacing

[Stevesixty7]

4 minutes ago, eddie eastwood said:

usually the blower rheostat needs replacing

Easy fix? Expensive?

[Stevesixty7]

I have noticed that the a/c only works (light comes on switch) on setting 1, 2 and 3 but goes off on setting 4. Could it be a/c related? I'm really hoping it's something quick and easy, I mean how can something work fine when you get out of the car and then not work when you get back in 10 minutes later?

[isetta]

 "I mean how can something work fine when you get out of the car and then not work when you get back in 10 minutes later".

Yes, anything electrical can work for years and one day stop.   eg. light bulbs - they don't play up gradually. they work - and then all of a sudden do not. All electrical stuff can go the same way.

Don't know about the aircon, but blower only on number 4 is a common problem.  the resistor pack (which reduces the power to the fan motor on speed 1/2/3 burns out- or the thermal protection fuse on the resistor pack burns out). On speed 4, it does not use the resistor pack, the power goes straight to fan motor. 

had this problem on my focus mk1 twice.  the real cause was stiff fan motor bearing causes an overload on the resistor pack. Once I had realised that was the cause and fixed the fan motor bearings, it did not fail again 

[isetta]

pic of resistor pack (fits into air trunking behind glovebox on my mk1 focus).  the bit at the bottom right is the fuse. On mine it was the fuse both times. got fuse on eBay for very little cost. had to solder on in place of the old one.  Note that these fuses blow from heat and not current. They have a temperature rating on them. if the resistor pack gets too hot then then fuse fails before a fire occurs.

Most people just replace the whole resistor pack.

[Stevesixty7]

Thanks for that mate, much appreciated.

[mjt]

19 hours ago, isetta said:

Note that these fuses blow from heat and not current

. . . . . so you have to be very careful when soldering them. You should use a heat shunt - gripping the wire with pointed nose pliers would probably be sufficient - to prevent the heat of soldering conducting back into the fuse.

[Stevesixty7]

Picked up a resistor pack today and have just fitted it, success. Many thanks again isetta.

[Stevesixty7]

The fuse looked fine too so maybe the unit just packed in.

[Stevesixty7]

Is this worth putting in the common problems thread to potentially helping others down the line?

[Stevesixty7]

Here's the old one. 

 

[isetta]

not sure if the fuse visibly look different when blows or if it blows inside with no outward sign. A circuit tester on the fuse will show if current still passes through it or if blown. If blown, it might have been caused by a fault like I had, stiff bearings in the fan motor.  It was a long time ago, but I seem to think the fan motor was not hard to remove and is behind the glovebox. 

If it goes again, don't just replace the resistor pack again, first check the fan motor spins freely.

[FatHead1979]

When I did mine a few weeks ago (whilst I had the dash out for the heater matrix) all the green "packaging" on mine was cracked, looked well tatty although it was 12 years old.  I couldn't see any obvious sign of physical failure but replacing it fixed the issue so it was clearly knacked.

[Stevesixty7]

On 27/11/2017 at 9:18 AM, 1979Damian said:

When I did mine a few weeks ago (whilst I had the dash out for the heater matrix) all the green "packaging" on mine was cracked, looked well tatty although it was 12 years old.  I couldn't see any obvious sign of physical failure but replacing it fixed the issue so it was clearly knacked.

Same as mine really, no sign of cracking though, I'm hoping it just gave up after 15 years and had nothing to do with motor bearings. The pack I removed had Ford on it too, so that gives me hope that the unit was original.