Fan control

Calfskin · Post by **Calfskin** » Fri Jan 27, 2006 7:16 pm

Hi guys. Its been almost a week of problem free motoring since I had the glow plugs done and now another fault has raised its ugly head - the fan control has an intermittant fault where it doesn't work sometimes. The control just swivels while controling nothing.

It comes back during normal driving or with a well placed thump to the dashboard. I think its a dodgy fan control as it does work although when it does, it sounds rather weedy sometimes.

Am I right? And having the dashboard apart I can see that it appears easy enough to replace, am I right again? LOL

Your help, as always, will be greatly appreciated.

Calf.

jeremy · Post by **jeremy** » Sat Jan 28, 2006 8:52 am

They all go like that eventually - can be many reasons - from motor brushes, motor connectors, failed transistors, incorrect circuit board manufacture, and dirty variable speed control or a failed relay.

I sorted mine recently - and when functioning properly you should have variable speeds, with a full speed when the knob is turned fully clockwise. This is marked by a relay above the steering column clicking in and shorting out the transistor control unit.

Many cars have an incorrrect circuit board (mine included) and when I made the mods described by Tom I had full speed for the first time!

I think you'll find it all in this link. Pictures of the circuit board and its mods are on Toms site - follow the link.

http://www.frenchcarforum.co.uk/forum/v ... ght=heater

jeremy

sleepy0905 · Post by **sleepy0905** » Sat Jan 28, 2006 10:21 am

Mine did axactly this i replaced the circuit board in the fan unit no cure in the end i replaced the fan and hey presto cured i have had no more problems for over a year now it turned out to be a worn out armature in the motor.

Cornishbx16v · Post by **Cornishbx16v** » Sat Jan 28, 2006 11:01 am

the small plate bit that plugs into the side of the blower unit is often the cause of failed units ( i cant think of its proper name!!! -maybe the rheostat??)! mine went ages ago and ihave finnaly got roudn to replacing it!
simple chaep job! failing that it could be the circuit board??

tom · Post by **tom** » Sun Jan 29, 2006 9:25 am

Go to the BXPress column on the club homepage. Where it says "Last month", click the link three times and you will find a blow by blow account of repairing and overhauling heater blowers.

tim leech · Post by **tim leech** » Sun Jan 29, 2006 10:24 am

Resistor timmo?

Vanny · Post by **Vanny** » Sun Jan 29, 2006 10:42 am

its not a resistor but a transistor, took me ages to find the resistor (its not there) but the haynes managed to show me the light and the dodgy power transistor!

If anyone is replacing the Bitron unit please let me know as i'm keen to get hold of dead ones and see if they can be overhauled, would be good to make a supply of available spares!

tom · Post by **tom** » Sun Jan 29, 2006 10:48 am

Vanny. Been there, done that. Bitron units cannot be overhauled or fixed as they contain two custom ULAs.

Vanny · Post by **Vanny** » Sun Jan 29, 2006 11:19 am

bugger, scrap that then!

Mines dieing anyway so i guess i'll have a dead one of my own soon, shame i dont have a spare

Clogzz · Post by **Clogzz** » Mon Jan 30, 2006 1:50 pm

Not sure if it applies to the BX, but on the Xantia, it's not the internals of the Bitron that fail, but intermittent contacts on the pins.
The pins are tinned with solder, and they need a good scrape.
I scraped them with the rough end of a broken piece of metals hacksaw blade, and then swept out the scraps of solder, and it's been good since.
I had tried previously to clean them with a little blunt screwdriver, and then squirted them with WD40, but that was only good for 3 days.

DavidRutherford · Post by **DavidRutherford** » Mon Jan 30, 2006 6:55 pm

I was under the impression that Bitron units were only fitted to (and needed on) Aircon cars?

tom · Post by **tom** » Mon Jan 30, 2006 7:01 pm

I think it is a generic Xantia fan controller, applicable to both types. Many more Xantiae had aircon than BXs, being inherently less cool.

You do have a point, though. BXs don't have Bitrons!

What does Vanny think he's doing.

Over here, boy. What's that in your hand? Explain yourself.

DavidRutherford · Post by **DavidRutherford** » Mon Jan 30, 2006 7:07 pm

tom wrote:Many more Xantiae had aircon than BXs, being inherently less cool.

Indeed!

I know for sure that the 405 and 306 ranges were only fitted with bitron units if they had A/C fitted, lesser models simply having the 3 speed relays (slow speed and high speed) controlled by a dual-temperature radiator switch.

I also seem to remember the same being true of early Xantiae: Bitron for A/C and thermo-mechanical switching for non-A/C.

It would certainly make sense that if you can "get away" without having a Bitron unit, so much the better.

ed4ferrets · Post by **ed4ferrets** » Sat Aug 12, 2006 9:01 pm

tom wrote:Go to the BXPress column on the club homepage. Where it says "Last month", click the link three times and you will find a blow by blow account of repairing and overhauling heater blowers.

Cheers Tom, your earthing bodge has got the blower going, it was flatlining before

Vanny · Post by **Vanny** » Mon Aug 14, 2006 6:21 pm

Now its been brought back up, just what is a 'Bitron' Unit? i THought Bitron was just a brand, and they did power control electronics (relays etc) so if Bitron units are only found on aircon cars, what are they and what do they do?