Fan Heater Speed

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MULLEY
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Fan Heater Speed

Post by MULLEY »

The fan speed has always been a bit on the low side, but if the dial was wiggled a bit then it would come on a fair bit stronger. Typically as its now winter, there is very little fan speed even when wiggling, however the faster i drive the more the fan speed seems to pick up. There is still plenty of heat regardless of speed. Does anyone have any ideas of what might be the issue (recently had new bulbs put into the heater unit & it looked fine)?
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mat_fenwick
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Re: Fan Heater Speed

Post by mat_fenwick »

Check the contacts between the knob and PCB; also the PCB tacks for wear. There are two different types of contact (that I've seen - there may be more) - either a thin springy contact strip or a something that looks like two ball bearings joined together, pressed against the PCB by a couple of tiny springs. Careful not to loose then when removing the knob.

The link with road speed may just be airflow spinning the motor faster; can you monitor the motor voltage whilst driving along? You've reminded me about the 12 V fan heater, will try and dig it out tonight :oops:
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Re: Fan Heater Speed

Post by citronut »

if the fan speeds up as you drive faster you might find your baterry is not charging up or holding full charge, so the faster the engine is spinning the alternator is chucking out more charge

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Re: Fan Heater Speed

Post by Vanny »

mat_fenwick wrote:The link with road speed may just be airflow spinning the motor faster
The ram air effect on the BX is mostly down to two issues absolutely dread full intake to the fan, and a body hole size (leakage from the body through poor seals, body air outlets etc) can be measured in square metres, where normally you aim for something in square centimetres.

What is really needed is a top hat over the blower intake to stop the intake of the blower taking air directly from the high pressure region at the base of the windscreen. The ram effect is considerably worse on an air con car as the intake points towards the engine and not the firewall.

The body air outlet (those grills on the rear quarter) are MASSIVE, probably double what they need to be, so air flow so quickly out of the car, that at high speed no cabin pressure builds up to resist the air flow coming in.

Unfortunately this sort of understanding wasn't available to Citroen until quite recently, hence the poor design on the BX. The only real solution to ram air is to fit recirc units from an air con car and keep them in recirculation mode, blocking off the inlet path through the motor.

You could try a thick piece of open cell foam in the body air outlet as well, that should reduce how fast the air falls out!
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Re: Fan Heater Speed

Post by MULLEY »

Tonight in the dark with the aid of a torch i found a couple of connectors, sprayed some plus gas & worked them in & out a few times. Fan is still dead as a dodo, i even gave the housing a belt with my hand incase it was sticking, nowt happening :( Could it possibly be somthing as daft as a fuse & if it is any idea of which one i need to have a look at?
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1990 Gti 8Valve SOLD - looks like it's been scrapped
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Re: Fan Heater Speed

Post by rutter123 »

worth looking at the carbon brushes on the fan motor, these can build up a lot of crap where they touch the armature causing slow running, had a similar prob with mine, gave it a good clean up with brake cleaner and fitted a new resistor at same time. hey presto good as new. think i sourced carbon brushes from a vacuum cleaner or similar about 4mm x 4mm with 10mm length
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Re: Fan Heater Speed

Post by Defender110 »

Have you connected the 2 earths ; motor earth to lamp earth as per 'the definitive heater mod' in tech questions section? Thats what cured mine and a lot of others? The motor earth burns out somewhere and a simple repair is just linking it to the lamp earth in the heater switch panel.
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Re: Fan Heater Speed

Post by mat_fenwick »

If it's now stopped rather than just slow, /\ yes, I'd check that first as that seems in my experience to be the most common problem.
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Re: Fan Heater Speed

Post by electrokid »

Brushes can wear out of course...
think i sourced carbon brushes from a vacuum cleaner or similar
Ok for a temporary fix but low voltage DC brushes contain much more metal than high voltage AC brushes which are practically all carbon - are softer - and will wear out more quickly. Probably best to find brushes for a battery power tool that are large enough to file to the right size.
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1992 TXD - Scrapped in March 2014
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Re: Fan Heater Speed

Post by MULLEY »

Righto, i followed the dismantaling proceedure as per the sticky which was great :) I fitted a new board & whilst the bulbs lit up like the old one, there was no airflow. I presume i've missed the point possibly & because the motor earth is knackered, would the modification be the only way to actually solve the fan issue except for a replacement fan?
2002 C5 2.0 HDI Estate - Jasmine - Now SORN
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1992 TZD Turbo - Bluebell - My daily
1991 Gti 16V - Blaze - crash damaged, will get repaired.
1990 Gti 8Valve SOLD - looks like it's been scrapped
2002 Mini Cooper S - SOLD - i miss this car
1992 TXD - Scrapped in March 2014
1988 CX 25 GTI Turbo2 - SORN
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Re: Fan Heater Speed

Post by mat_fenwick »

If the fault is with the earth, then a new motor won't help either! If the front dash panel is off, just run a temporary good earth to the middle terminal of the 5, and see whether it bursts into life.
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1991 Gti 16V - Blaze - crash damaged, will get repaired - SORN
1990 Gti 8Valve SOLD - looks like it's been scrapped
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1992 TXD - Scrapped in March 2014
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Re: Fan Heater Speed

Post by MULLEY »

Cheers Mat, i'll have to try that next weekend as the car is used daily, pain in the butt really. I also noticed that the cigarette lighter no longer lights up, i did connect it up before putting the dash panel back on, is there anyway of cocking this up?
2002 C5 2.0 HDI Estate - Jasmine - Now SORN
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1991 Gti 16V - Blaze - crash damaged, will get repaired.
1990 Gti 8Valve SOLD - looks like it's been scrapped
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1992 TXD - Scrapped in March 2014
1988 CX 25 GTI Turbo2 - SORN
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Re: Fan Heater Speed

Post by mat_fenwick »

There's a double connector (thick yellow wires) for the socket itself, plus a smaller single connector for the illumination. Also, the bulb holder relies on contact with the socket body to make an earth connection, so if it's been shifted it may no longer be making contact?
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1992 TZD Turbo - Bluebell - SORN
1992 TZD Turbo Estate - SORN
1991 Gti 16V - Blaze - crash damaged, will get repaired - SORN
1990 Gti 8Valve SOLD - looks like it's been scrapped
2002 Mini Cooper S - SOLD - i miss this car
1992 TXD - Scrapped in March 2014
1988 CX 25 GTI Turbo2 - SORN
1996 - AX Memphis 1.5D - Dream - SORN
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Re: Fan Heater Speed

Post by MULLEY »

Yup, there are those 2 connectors, i guess i'll have to take the clock tray out & have a look to see what's going on.
2002 C5 2.0 HDI Estate - Jasmine - Now SORN
2011 Mini Cooper D Clubman - SOLD
2016 Mercedes A180D Sport - Auto refinement
1992 TZD Turbo - Bluebell - My daily
1991 Gti 16V - Blaze - crash damaged, will get repaired.
1990 Gti 8Valve SOLD - looks like it's been scrapped
2002 Mini Cooper S - SOLD - i miss this car
1992 TXD - Scrapped in March 2014
1988 CX 25 GTI Turbo2 - SORN
1996 - AX Memphis 1.5D - Dream - SORN

I'm not just a username, i'm also called Matthew.
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