Heater Control Issue

[KTP]

my heater controls dont seem to be working right.

the fan speed setting '1' isn't working at all, yet 2, 3 and 4 seem to be fine.

any ideas? :confused:

[Black-Cat]

I'm sure there's a resistor card that over time can find it's circuits damaged, I had a similar problem on a previous car and got a replacement from a dealer and cured it.

It was situated on the left hand side of the dash under the glovebox, has a small plug that fastens onto it, dunno if it'll be the same on your car though...

Hopefully this'll help...

[Browny_37]

Series resistor, had this go on my Octavia last month.

But i only had fan speed No. 4!

Was either freeze or have headache, i chose to freeze.

Think it was around £26-£36 for the part, i assume its the same part no as the octavia not sure if its the same on the mk2 octavia though.

[AndyPandy]

the reason 4 is working ,and the other positions are not is because resistors are only used in positions 1,2,and 3. the full 12 volts goes to the fan motor.

[jacko203]

I'll dig out my fabia haynes manual in a bit, but I've just done this on a Mk3 golf and assume it's a similar set up.

Resistors convert current into heat, so the resistor pack is protected by a thermal fuse. Positions 1-3 are reduced power dependent on resistor strength (resistance), position 4 is straight through with no resistor knocking off voltage - therefore max fan speed.

If just 4 is working, I would suspect the thermal fuse had blown (pos 4 has no resistor remember, so no need to be protected by thermal fuse). Since 2, 3 and 4 are OK, the thermal fuse is fine. In my mind there are two options:

1) No. 1 resistor is knackered

2) Speed selector switch is cacked

I've not done this on the fabia, but I imagine that the resistor pack is right next to the blower, i.e. behind the glovebox. Glovebox is a piece of **** to take out, just need a torx ?T20 maybe 25. The resistor pack will be near a lead/connector going into it with 5 wires coming out (at a guess).

If you remove the resistor pack, you could measure the resistance of all the resistors with a multimeter. Also, if the thermal fuse is obvious (cylinder job on top?) then check continuity of that, but it won't be gone. First though, I'd remove the connector, switch the ignition switch to II (i.e. accesories on) and then get a multimeter on the incoming (to the resistor pack) lead. You should get 12v from each pin in turn as you select 1, 2, 3 and 4 - obviously 1 pin at a time, there will (probably) be 1 pin live for each fan speed setting. If you have 12v on one lead when the switch is at setting 1, then you know it's downstream of this, almost certainly the resistor pack.

Hope that helps - as I said, this is based on the golf I did yesterday but I imagine it's the same.

Rob

PS - Strangely enough in the golf, settings 1, 2 and 3 were gone. Ah! I thought, resistor pack - the fuse was fine, so I butchered it testing resistances, only to discover that the switch had gone in positions 1, 2 and 3! What are the chances, eh?!

[jacko203]

PPS If the switch is knackered then I don't envy you trying to get that unit out in the fabia dash! In the golf, I could pull off the fascia front with the markings on, pull off the switch knob and clean the contacts with wire wool and WD40. With a bit of judicious bending of copper contacts, worked fine.

Obviously if you do end up doing this, ignition off! Also when playing with the multimeter before try not to short anything or you'll soon run out of fuses.

[KTP]

thanks for that infio, i'm pretty sure the switch is fine, i usually leave it on no.1 setting all the time as its quieter and doesnt heat the car too much. i only noticed it one day when the car felt cold and i realised the heating wasnt on.

i'll try replacing the resistor pack. i've had the glovebox out a couple of times before so i know how easy it is to do

[jacko203]

While you have the resistor pack out, I would try either swapping in another off another car or multimeter testing the leads - even a 12v bulb or buzzer (eg car interior light bulb) with 2 wires attached to test that you are getting current through on setting 1. I'm guessing a resistor pack will cost about 30 quid, whereas testing it first would be 5 mins MAX. It just seems a bit odd to me that 1 resistor would go (not familiar with high power resistors, just from home electronics).

Anyway, hope it is the resistor pack for convenience sake.

Cheers

Rob

[devonutopia]

Sounds like resistor pack to me. Had the same thing happen. Was able to get a pack out of a scrapper fabia locally to me and fit it. Was a bit of a squeeze getting the old hand in there though - still not how sure how sausage fingered lummox claims to be able to do it easily. I suspect it involves KY :eek:

[Mike B]

I suspect it involves KY :eek:

Everything is possible with sufficient lubrication Jason!!!

[national]

Search on here for HEATER BLOWER it is all explained with pictures

It is amazing what search finds when you need info

However if everyone used search and got the answer then there would be no Forum and the site would be deed deed I tell ye :-)

National