Heater airflow problem

dazed and confused · Unread post by **dazed and confused** » 18 Jun 2010, 17:18

I have recently purchased my first Citroen, a T reg Xantia 1.9 td with (surprisingly) an issue or two. Having replaced the blower which was not working as it was practically burnt out, It now runs only on the full speed setting but nothing comes out of any of the vents, regardless of the position of the screen/head/foot control or the fresh air/recirculate control. the only effect moving these has is to change the noise thats going on. Any ideas anyone please?
The aircon seems to be working, the pipework gets cold and the radiator fans chime in when aircon is switched on.
Also the big Bosch ecu at the fan belt side of the bonnet had some bad corrosion on the pins, I have cleaned this as well as I can but I think it's still a bit iffy, one of the pins is quite bendy and the plug on the cable is really hard to clean with the holes being so small. What does this actually control, is it to do with the heater/aircon?
The horn doesn't work either! When I eventually located it I took it off, cleaned the contacts and with a bit of tweaking got it working from a battery. Sorted I thought, but no. Fuse 7 is good, so there is obviously a wiring fault. Is there a relay in the circuit, if so whereabouts?
Any help would be greatly appreciated

Clogzz · Unread post by **Clogzz** » 19 Jun 2010, 15:02

Welcome to our troubles, d & c.

The new blower is probably faulty with shorted transistors causing it to spin at full speed.
You should be able to return it until you get a good one.
We have plenty of topics about blowers, and I’ll go digging.

Lack of air flow is usually due to a blocked pollen filter under the passenger’s dash.
I’m not aware of aircon controls in the engine room’s ECU, and it’s not a common cause of problems.

No idea about the horn fault, never been there.
We have experts in all fields, and they shouldn’t be far behind.

Unread post by **CitroJim** » 19 Jun 2010, 21:58

Welcome D and C

The blower can be fixed if you are handy with a soldering iron and this guide shows how. You need a par of MJ11015 transistors and these are available from Farnell.

Note that the blower speed regulator transistors are at fault ONLY if the fan blows at full pelt as soon as the ignition is turned on and is not controllable at all from the slider.

This thread gives other troubleshooting tips...

Lack of air can be caused by the recirculation flap stuck midway due to a kink at the slider end of its cable. With the blower out you can see the recirculation flap. Make sure it is fully in the fresh air position. The cable is impossible to replace easily and most of us live with it stuck in fresh.

On a MK2 Xantia, the horn issue is most likely the airbag mounted horn push buttons. Often someone has the wheel and airbag off for an unrelated reason and forgets to reconnect the horn wiring or the rotating joint has failed. They're a tad fragile and must be properly aligned on refitting. "Joint" is a misnomer as it's actually a coil of wire wound on a spool and the ends often break. There is a similar arrangement for the airbag and radio remote controls...

Unread post by **Peter.N.** » 19 Jun 2010, 22:33

I suppose you haven't got a Peugeot blower, look the same but run backwards.

Peter

dazed and confused · Unread post by **dazed and confused** » 20 Jun 2010, 14:57

Thanks for suggestions. Yes the blower is from a Peugeot, breaker boys said they were the same. Can I just swap the wires into motor to reverse it, or is it the angle of the blades thats different? Unfortunately I have thrown the old one away in a fit of garage tidying, so cannot compare. Pollen filter seems not too bad, have given it blast with airline. Fresh air flap moves freely.
To clarify; the blower comes on full speed with the speed slider fully to the right, when it is moved left to reduce speed the blower cuts out. It's all or nothing.
As for the horn, I can't even begin to remove the airbag! What size Torx bit do I need? T25 is too small and T 30 seems too big

Is there such a thing as T27.5 ?

Clogzz · Unread post by **Clogzz** » 20 Jun 2010, 15:22

The angle of the blades is different, so it would have to go back for the right one.

Ideas here for a slider fault:
http://www.frenchcarforum.co.uk/forum/v ... hp?t=23767

The airbag screws are at least T30, don’t remember, but they are angled outwards, so can be difficult to grab.
There are no odd sizes, it goes 20-30-40.

Unread post by **Peter.N.** » 20 Jun 2010, 15:23

I believe the angle of the blades is also different, I think Jim commented on this a while back.

Unread post by **Peter.N.** » 20 Jun 2010, 15:24

You just beat me Clogzz, all the way from Australia too!

Clogzz · Unread post by **Clogzz** » 20 Jun 2010, 15:30

We’re flying fast here, Peter.

As our chief Jim wrote, two answers are better than none.

MikeT · Unread post by **MikeT** » 20 Jun 2010, 17:04

There is a T27, I've got one in my set.

Clogzz · Unread post by **Clogzz** » 21 Jun 2010, 14:44

Congratulations Mike, that’s a very complete toolset, and you’re doing abnormally well.

The airbag screws must be T30 because I undid them with an el-cheapo set of bits going 5-10-15-20-30-40, and don’t remember ever using the T40 bit, even though it’s as rusty as the other bits.

Unread post by **CitroJim** » 21 Jun 2010, 17:01

Airbag is T30.

T27 is only used in 4HP20 autoboxes as far as I know. I had to buy one specially for that!!!

Unread post by **admiral51** » 21 Jun 2010, 20:08

CitroJim wrote:
Lack of air can be caused by the recirculation flap stuck midway due to a kink at the slider end of its cable. With the blower out you can see the recirculation flap. Make sure it is fully in the fresh air position. The cable is impossible to replace easily and most of us live with it stuck in fresh.

I agree with you Jim on the replacement of the cable,probably best left to when the heater matrix is replaced

It is possable to straighten the cable if the kink is indeed in the heater control box.Once the radio is removed and the retaining screws for the heater control unit removed you can,as im sure you are aware being a member of the "matrix club"

lift the control unit out a few inches,remove the lid and have a play about with some long nose pliers

Colin

Xaccers · Unread post by **Xaccers** » 21 Jun 2010, 20:14

CitroJim wrote:Airbag is T30.

T27 is only used in 4HP20 autoboxes as far as I know. I had to buy one specially for that!!!

It's also used for the "fun screw" in the top of the flying saucer on Bosch pumps

dazed and confused · Unread post by **dazed and confused** » 21 Jun 2010, 23:16

Changed blower today, air now issuing from vents at gale force,almost dislodged my hairpiece!!

Breaker boss reckoned difference depended on whether fitted with aircon or not, but I think you guys have the truth of it, am sure 1st blower came from aircon 406. Speed slider gives more moderate blast when at auto position so I think I can live with that for now.
Obtained T27 bit and that fits, no way can I make T30 fit!?! I must have a friday model

(Curse these fiendish french, I thought Renault had the monopoly on odd sized fastenings!)
I wont get a chance to look at the horn until the weekend, but will let you know how I get on.
Would just like to say thanks and what a fab friendly fact filled forum this is.
As my granny used to say a trouble shared is a trouble halved, and you'll never learn to walk on the ceiling just by standing on your hands!