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        General >> Problems >> Heater Blower stopped
        
(Message started by: Technology2005 on Jul 8th, 2010, 5:45pm)
Title: Heater Blower stopped
Post by Technology2005 on Jul 8th, 2010, 5:45pm
Yesterday whilst ferrying the kids about the heater blower suddenly stopped. The climate control was set to "Lo" so the fan was on full as expected.

Now when I try and operate the blower either on Auto on the climate control or manually using the rotary speed control nothing happens.

So far I have done the following:

Reset the CC Panel (no fault codes before or during reset)
Checked fuse F29
Checked for Relay R28 before realising that with SATC I shouldn't have one on this car for the blower?

I also followed the HBC test procedure here http://www.fordscorpio.co.uk/hbc.pdf and my results were a bit odd!

I checked the voltage HBC side across  the Black/Red and Violet/Orange wires with the blower speed set to Max, Middle and Minimum respectively and got 7.8V, 8.5V and 8.4V instead of the correct 10V, 5V and 3V.

Also the Control Signal connector which should have the White/Blue and Brown/Blue wires only has the Brown/Blue wire fitted. I double checked for detached wires but the connector only seems to have had the one wire fitted from new? Anyway, the voltage across the Brown/blue wire to earth was 4.5V at max and 1.9V at minimum.

Anyone got any ideas where the fault is? The voltages for the HBC side across  the Black/Red and Violet/Orange wires are clearly wrong and do not vary the correct way when the control is applied, but despite there being a voltage to the Blower Motor the blower stays off.

Am I looking at a faulty fan motor (odd that it stopped whilst on full), a faulty HBC module or is the Climate Control Module itself suspect?

David

PS: Forgot to say that the car is a 95N 2.0L Ultima Auto
Title: Re: Heater Blower stopped
Post by Cosray on Jul 8th, 2010, 8:27pm
... did you measure the fanmotor's resistance?
(odd that it stopped whilst on full) you say but a burnt coil would do that at top performance; not while being idle.

So in fact measuring the coils Ohm's resistance?

It's either open -- and then it will not work -- or say 6 Ohms which at 12 V would draw 2 Amp. I forget the exact resistance but again, either it is open circuit or anything between 6 and 2 Ohms.

Meauring voltages delivered from the control unit is not significant since it is pulse mode driven  over a coil which no multimeter can properly read.

The circuitry before the HBC is rather complex. In fact it is 3 units: the control panel, the control unit and the HBC. Many things can go wrong there.

Most often the HBC goes haywire; just replace it with one from the breakers with the long coolingfin!

Alternatively the connector between the units gets corroded ( as all 300 Scorpio connectors have corroded after 10 years by now!)

Also, inside the control panel on the dash which is easily detached you will find 3 potentiometers which are in need of spraying and lubricating.

When open do replace the lightbulbs!

HTH
Ray
Title: Re: Heater Blower stopped
Post by Mike H on Jul 8th, 2010, 8:43pm
FWIW one of the previous repairs on mine (before my time) was "replace fan motor resistor" (?)
Title: Re: Heater Blower stopped
Post by Technology2005 on Jul 8th, 2010, 8:50pm
Hi Ray, thanks for the reply. I have basically only followed the guide for troubleshooting the HBC up to now. I haven't measured the fanmotor's resistance as the thing is a little hard to actually get at, but am hoping that replacing that would be a last resort! Also I didn't detect the wonderful aroma of burning electrical circuitry that I have become accustomed to over many years of working with PC's and laptops so fingers crossed the motor is ok.

All the connectors I took off at the HBC seemed to be free of corrosion, but cannot vouch for other connectors before or after the HBC. I agree that on a 15 year old car the likelihood of dodgy electrics due to corrosion is significant.

I will have a look at the control panel and (as other members seem to have done) possibly take out the SATC module itself to examine the circuitboard for dry joints or to replace.

I reckon replacing the HBC is the easiest and quickest "test by substitution" at this stage and after that the SATC control module itself.

Regards,

David
Title: Re: Heater Blower stopped
Post by Cosray on Jul 8th, 2010, 8:50pm
Mike: ... that resistor-situation applies to the lower-option 3-dial control panel; NOT to the SATC which is pulse-width driven, not by resistor.

Ray
Title: Re: Heater Blower stopped
Post by Cosray on Jul 8th, 2010, 8:51pm

on 07/08/10 at 20:50:21, Technology2005 wrote:
Hi Ray, thanks for the reply. I have basically only followed the guide for troubleshooting the HBC up to now. I haven't measured the fanmotor's resistance as the thing is a little hard to actually get at, but am hoping that replacing that would be a last resort! Also I didn't detect the wonderful aroma of burning electrical circuitry that I have become accustomed to over many years of working with PC's and laptops so fingers crossed the motor is ok.

All the connectors I took off at the HBC seemed to be free of corrosion, but cannot vouch for other connectors before or after the HBC. I agree that on a 15 year old car the likelihood of dodgy electrics due to corrosion is significant.

I will have a look at the control panel and (as other members seem to have done) possibly take out the SATC module itself to examine the circuitboard for dry joints or to replace.

I reckon replacing the HBC is the easiest and quickest "test by substitution" at this stage and after that the SATC control module itself.

Regards,

David


Yes quite - you seem to be one of my school ;-))

... do I know that smell...

Ray
Title: Re: Heater Blower stopped
Post by Technology2005 on Jul 8th, 2010, 8:53pm

on 07/08/10 at 20:43:17, Mike H wrote:
FWIW one of the previous repairs on mine (before my time) was "replace fan motor resistor" (?)

Hi Mike, I spotted the fan motor resistor on one of the pages on here, http://www.fordscorpio.co.uk/images/acducting1.gif  but I suspect it isn't easy to get at. I have suspicions that this may be the culprit, but have no basis other than the way the fan suddenly stopped. As Ray mentioned it could also be the motor itself, but in either case I couldn't smell any burning that usually goes with components fryings themselves!

David
Title: Re: Heater Blower stopped
Post by Tompion on Jul 8th, 2010, 8:55pm
Some only have the one wire as you mentioned.

Could be the fan seized or the commutator worn out, (you should be able to find some old posts about this).
With the HBC removed you can just about get a finger on the fan and see if it moves.

You can get an idea of the fan layout here:
http://www.fordscorpio.co.uk/fanrepair.htm
Title: Re: Heater Blower stopped
Post by Cosray on Jul 8th, 2010, 9:02pm

on 07/08/10 at 20:53:58, Technology2005 wrote:
Hi Mike, I spotted the fan motor resistor on one of the pages on here, http://www.fordscorpio.co.uk/images/acducting1.gif  but I suspect it isn't easy to get at. I have suspicions that this may be the culprit, but have no basis other than the way the fan suddenly stopped. As Ray mentioned it could also be the motor itself, but in either case I couldn't smell any burning that usually goes with components fryings themselves!

David


Technology2005
IF you have a SATC THEN you have NO resistor. Wrong page of the manual I am afraid.

SATC drives the fan by pulse-width control, so therefore measuring Voltages either DC or AC readings is not valid.
Ray
Title: Re: Heater Blower stopped
Post by Technology2005 on Jul 8th, 2010, 9:05pm

on 07/08/10 at 20:55:34, Tompion wrote:
Some only have the one wire as you mentioned.

Could be the fan seized or the commutator worn out, (you should be able to find some old posts about this).
With the HBC removed you can just about get a finger on the fan and see if it moves.

You can get an idea of the fan layout here:
http://www.fordscorpio.co.uk/fanrepair.htm


Thanks for clearing up the single control signal wire mystery :)

I already had a read of the fan repair page, which made me really hope that the fan motor itself is ok! Good to know that you can reach the fan motor with the HBC out. Might give it a little turn (with all power off!) just to check if it has seized although it didn't make any strange noises as it stopped. I remember seeing the page about the worn commutator as well in the past. If I remember the guy managed to angle the brushes to make contact somehow. But like I say I really hope it isn't the motor :)

David
Title: Re: Heater Blower stopped
Post by Technology2005 on Jul 8th, 2010, 9:07pm

on 07/08/10 at 21:02:46, Cosray wrote:
Technology2005
IF you have a SATC THEN you have NO resistor. Wrong page of the manual I am afraid.

SATC drives the fan by pulse-width control, so therefore measuring Voltages either DC or AC readings is not valid.
Ray


Ahhh, thanks for clarifying that Ray.... Well there goes that theory...back to HBC substitution methinks!

David
Title: Re: Heater Blower stopped
Post by Cosray on Jul 8th, 2010, 9:17pm
... quite my friend, quite...

Ray
Title: Re: Heater Blower stopped
Post by Simmo on Jul 9th, 2010, 7:59am
David. If you look at the fan repair page and go to the last photo, click on it to enlarge, you will see a copper 'spring'. That is the area where the brushes are and you can feel that, just !!, through the aperture where the HBC sits.The best thing to do is give it a good dose of WD 40 or electrical cleaner and see if that helps. Gost (Bruce) had this problem a while ago and it did resolve it. Let us know how you get on. Mike
Title: Re: Heater Blower stopped
Post by Technology2005 on Jul 9th, 2010, 8:12am
Hi Mike, thanks for that tip.

Todays plans are to "rob peter to pay paul" !

Assuming that the fan doesn't appear seized I'm going to temporarily borrow the HBC from the other Scorpio to do the test by substitution. If that doesn't work I'll get some electrical cleaner on those brushes!

David
Title: Re: Heater Blower stopped
Post by Cosray on Jul 9th, 2010, 8:18am
Yes David, whenever you have a chance with these closed loop systems: cut and try and cannibalise is often the most effective approach for eliminating interdependent causes and guesswork.

Let us know how you fare!

Ray
Title: Re: Heater Blower stopped
Post by Simmo on Jul 9th, 2010, 8:21am
David. I've just located Here (http://www.fordscorpio.co.uk/cgi-bin/yabb/YaBB.pl?board=Advice;action=display;num=1246063400;start=0#0) a Tompion post which shows the parts of the motor and gives details of one of his famous 'bodges' !!.
Title: Re: Heater Blower stopped
Post by Cosray on Jul 9th, 2010, 8:26am
... excellent piece... Simmo could you copy that to "How To "section?

Ray
Title: Re: Heater Blower stopped
Post by Simmo on Jul 9th, 2010, 8:28am
Ray, ...doing it as you posted. :) Mike
Title: Re: Heater Blower stopped
Post by Technology2005 on Jul 9th, 2010, 8:29am

on 07/09/10 at 08:21:17, Simmo wrote:
David. I've just located Here (http://www.fordscorpio.co.uk/cgi-bin/yabb/YaBB.pl?board=Advice;action=display;num=1246063400;start=0#0) a Tompion post which shows the parts of the motor and gives details of one of his famous 'bodges' !!.

Aha! Yes I read that guide a while ago. Useful to have the link to it again!

Thanks

David
Title: Re: Heater Blower stopped
Post by Tompion on Jul 10th, 2010, 1:41am
My fan is still running, looking at the date of the post it must have done about 10,000 miles now.
Title: Re: Heater Blower stopped
Post by gost on Jul 10th, 2010, 10:17am
As Mike says, Iv had this problem twice now, and fixed it same way. Remove HBC control thingy, put finger in hole and find a spring, flick it a few times then spray loads of wd40 all over everything, now try fan in manual full speed, if it runs then leave it running for a few mins, works for me lol
Title: Re: Heater Blower stopped
Post by Technology2005 on Jul 13th, 2010, 9:37am
Sorted the heater blower problem.

I swapped the HBC module from the other Scorpio this morning and it cured the problem.

Thanks to all those who tried to help and finally I can drive a  car without slowly baking inside !

Now all I need is another HBC module to replace the one I robbed from the other car lol

David


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