Another Xantia Blower Thread - now fixed

[djadams]

Hi guys, first post on the boards here but I've been lurking for years since buying my first Xant, a 95 1.9td.

I'm now moving on to a Series 2 Activa (wanted an Activa for years!), but it has arrived with a couple of problems.
One of which is that the blower fan runs at high speed all the time, even with the engine off.
I thought I knew (from reading the many threads about Xantia blowers on here) what the problem was, so I ordered a pattern transistor pack for the blower unit. I fitted that, and with that fitted, the fan doesn't turn at all.
Having read another thread on here I started checking the voltage at the orange wire that talks to the speed control transistors from the climate ECU. I only get one voltage value regardless of what position the switch is in, but it depends on which transistor pack I have installed...

With the original transistor unit installed I seem to get a mostly constant 8.23 volts, regardless of engine running or not/speed selector position. Even though this should give a moderate speed, the fan runs like the clappers all the time.
With the new pattern transistor unit installed, I get a constant 0.2 Volts regardless, which should give me a high fan speed, but instead it doesn't turn at all...

Does this imply my climate ECU has died, or is there hope that the old transistor pack had died and the new one is simply the wrong part...?

Any help/hope very much appreciated!

Meanwhile I'll get on with fitting my steel wheels and winter tyres - she won't look so pretty, but she'll grip better than she does on her hard, perished old tyres...

[rory_perrett]

When you say that the blower fan is on full all the time with the engine on or off does it run when the ignition is off or when only when the ignition is on?
If the fan is running and you pull fuse 21 does it stop?
If the fan is running and you pull fuse 5 does it stop?

Rory

[djadams]

Hi Rory,

Thanks for the reply - the fan runs all the time the ignition is on, regardless of whether the engine is running or not. The fan does not run with the key off or in the "accessory" position. Pulling fuse 5 has no effect on it, pulling 21 makes it stop.

Cheers,
dan.

[rory_perrett]

Dan

Fuse 21 is the main supply to the fan, fuse 5 is the supply to the fan power relay which is loacated under the carpet just above the accelerator pedal.

Have a check to make sure this relay is operating correctly. Following Gadgegricey's (Dave's) experiences there may have been some "re-wiring" by a previous owner. But pulling fuse 5 should make it stop.



Rory

[djadams]

Well, that relay does do something. With the ignition on (and therefore the blower fan running), pulling that relay did make it stop, so one way or another the blower motor is getting it's power through that relay. I'm guessing It's item 8048 on the wiring diagram Jim shared (in another blower speed thread!). According to the diagram, that relay is ignition controlled, so as the fan does go off with the key, I think that relay is ok. Mystified as to why fuse five doesn't seem to affect it, so I may have to check where the signal to that relay is coming from.

But should that relay affect the speed control, do we think? Or just make the fan not work if the relay fails? I'm a little unsure as to exactly how the system works still...

[RoyChristie]

was/is the fan motor original in the car?
I recently fitted a fan blower from a S2 turbo petrol to my V6, got these symptoms -
... switched back to the original transistor pack on the new motor and all was fine.. no idea of the physics

[djadams]

Good question. I think it is, but I have no way of knowing for sure. It certainly pre-dates the two days of my ownership so far...
The chap I bought the car off seemed a genuine, decent bloke and he was surprised when the blower was misbehaving when I went to view it. That made me think it hadn't had a recent history of problems, anyway. I'm wondering whether the transistor pack I've bought off ebay is faulty (and the oe one has just died of old age) - but without another unit to hand to try out, It's a bit hard to say. Anyone got any experience of the ebay cheapie pattern parts?

[rory_perrett]

No the relay does not affect the fan speed in theory, however when I had a supply problem from fuse 5 to the relay it stopped the aircon, the blower motor and the heater flap from working. From the wiring diagram I can't really see why but assumed the ECU was getting upset. Once I had restored power from fuse 5 to the relay it all sorted itself out. You may have more than one fault I'm afraid. 8048 is the blower fan relay.

[djadams]

Interesting. As far as I can make out, the heater flap is operating correctly as when the interior warms up the air coming out of the vents cools down - so that side of things seems to be ok. I've been assuming the air con doesn't work because it's not been maintained for years - I was planning on an entertaining game of "hunt the leak" and a re-gas sometime next spring.
I will have a look at what's going on with fuse 5 and that relay tomorrow. There's a few other things to do, but getting to the bottom of this is fairly high priority.

[djadams]

Update!

I still can't fathom how the blower was running with fuse 5 removed, but it is now controllable...
I tried the local breakers on the off chance they had something suitable and sure enough they had a 406 with AC sat in a big muddy puddle.
I made my way over to it as carefully as I could and removed the similar (though not identical) blower unit. Brought it home for a tenner and removed it's transistor pack. Fitted that transistor pack into the Activa's blower unit and... Eureka! We have controllable fan speed.

Very pleased with that result, now I just need to try and get back the £20 I wasted on the cheapie transistor pack off ebay that didn't work...

Thanks to everyone for their help - the wealth of info on this forum is astonishing, and without it I'd've been properly scuppered.

The next little project will be a new anti-sink sphere, but that can wait for a bit I think.

[rory_perrett]

Glad you've got the blower fixed.

When you do the anti sink sphere, remember to remove the pipe first before you unscrew the sphere.

[MalcolmBrown]

I am struggling with the at first intermittent, now complete loss of blower function. The picture of the relays posted by Rory above doesn't look like that on my 1999 LX; there is a green relay which looked like the one marked with an arrow, but when I removed that (when the system was in the mood for working) the aircon green light lit as usual but the engine would not fire so I assumed it was a relay controlling the fuel injection.
Mine has another relay in between the main board and the floorpan which is blue and I cannot fully reach- could this be the relay I need to get at?