12 replies to this topic

[Giles]

I know that this has been discussed a lot in the past but I just wanted to warn people who are not already aware of this problem. The topic in question relates to the fan speed circuitry for the cabin airflow. The rotating switch on the dash changes the resistor which is used to supply power to the fan. The slower the fan speed the high the resistance. When the resistor is in operation, heat is produced. It appears that eventually, the resistor element burns out. Obviously, the slowest fan speed (ie 1 click on the knob) produces most heat so is most likely to fail. Once it does go (like mine) there isn't an easy solution. The resistor pack is not sold separately and a heater unit is a good few hundred quid. So what should you do? Well, it's pretty obvious. Don't leave your fan on 1 click all the time like I used to. I suggest leaving it turned off fully and then turn it on fully when you need demisting etc. It doesn't really do much anyway. Hope this is of help to someone. If anyone has any good ideas about replacement resistor packs, let me know. Giles

[MIKE_VX]

Cheers for the heads up - didn't know about this one. I generally drive around with it on the first setting, just to give a bit of airflow - I'll be changing to your proposed method from now on though!!

[Gouldy]

Hope this is of help to someone. If anyone has any good ideas about replacement resistor packs, let me know.

Not sure where the vx one fits in, but you can get them from other cars. The one on our Focus broke the other day. The replacement was about a tenner from the ford dealer. Don't see why it couldn't be modified to fit in place of the vx one.

Also, from what I've seen, the vx one is some rather Heath Robinson coils of wire. In the Ford one the resistive conductors were covered in a kind of high temp ceramic stuff.

Might be worth a go.

[rabidh]

Just to link stuff together, there's a thread on repairing the heater resistor pack -= here =-

I've found Rapid Electronics sell properly nice resistors for less than a fiver each. They'd be good if you want to do a long-lasting repair yourself.

Never got around to doing the resistor pack though. Out of interest, how many people here have a broken setting 1 on their heater?

[JawZ]

I have a broken setting 2 caused by some water which got to it...

[Steve Crisp]

Come-on you electronics people out there! It's been a bit too long for me to remember easily how to do it, but the parts would be: - 1 x power transistor with a heat-sink 3 x 1/2 watt resistors of different values. something to mount it on. This is only a DC motor that you wanna vary the speed on. In fact, you could change the facia switch for a "volume control", and feed that into a power transistor for an infinitely variable speed one - all for a few pennies! Volunteers? Steve

[JawZ]

I would happily buy one if they were to be made

[luna_s]

I was thinking of the potentiometer idea with the lever for the heat control too, getting rid of the bowden cable totally, but im pretty rubbish at electronics !

Edited by luna_s, 05 March 2007 - 05:51 PM.

[Giles]

Thanks for the replies everyone. If someone can put something together, I'd gladly pay good money for it. Don't trust my own soldering skills at the moment.

[rabidh]

You could replace the bowden cable for hot/cold with a pot (and a small oscillator) and a model aircraft servo (although you might want one of the bigger high-power jobs - i don't know how much force is needed for the panel in the heater). Thing is you don't really gain that much from it - and personally i think an oiled bowden cable may actually be more reliable Variable speed control would be nice, but it seems like a total pain getting the controls out of the dash. Personally I think a replacement for the resistor pack is the way to go. I was just thinking of a slab of aluminium with 2 100W resistors bolted to it, and 3 flying leads. You could then just cable-tie it somewhere where it wasn't going to move. It'd cost about £10 in parts looking at rapid electronics. I'd be willing to make some but the idea of doing the same bit of metalwork 20 times kindof puts me off. I asked Eliseparts and they'd be willing to stock/sell them (price permitting) if some got made, so I imagine they would be after quite a few.

[SteveA]

My number 1 setting is gone. I tried to repair it a while back but the unit is in a very tight spot, difficult to get at with screwdrivers or a drill.

[rabidh]

My number 1 setting is gone. I tried to repair it a while back but the unit is in a very tight spot, difficult to get at with screwdrivers or a drill.

Yeah, its a pain. if i recall correctly the header tank for the brake fluid is held on with a cable tie, and taking this off (as well as the vacuum hose, which just unplugs from the slave cylinder) really helps. My screws had rusted up too Another reason why just a plug-in solution would be good i guess - you could just leave the old pack in there.

[Steve Crisp]

Here you go. I think this'll do the job: -

http://www.maplin.co...oy=5m3#overview



Steve