Right I have a problem, fan doesn't work.
Basically so far I have stripped the controls and found the are no earths going to the circuit board apart from the light bulb part and I am struggling to answer why this is happening I've changed over the rheostat type thing in the fan box still nothing. Has anyone come across this before?
Any comments are welcome.
1991 Citroen BX 16v - Red
1991 Citroen BX 16v - Silver
1992 Citroen BX 16v - White
1989 Peugeot 205 MI16 - Miami Blue
2002 Peugeot 406 est. HDI110 exec - Dark Blue
2006 Citroen C6 2.7HDi Exclusive - Storm Grey
Scrapped:
G650PGX 1989 ph.2 red BX 16v
G-VOT 1989 ph.1 White BX 16v
There is a thread where I got mine going some three or four months ago where the guys covered most of this territory. Also DIY BX website has a reasonably good item on testing the best up.
If it is earth on the heater control PCB there are two. If the light works so does that earth so you can 'borrow' it with a jumper to the other for the control. Should work if that is the fault, but it is more likely poorly aligned or dirty rheostat. Again you can jump power to this from the known live feed to prove the heater control board. That leaves the scraper. You can re-profile a bent disc using hot water or kettle steam. A certain amount of pressure is needed for contact. To much and the applied silvering on the PCB will wear out.
You can test the motor itself from its connector directly.
Miguel - 16 TRS Auto S, light blue, 43k miles - £450
Pluto - 14 E S, White, 105k Miles - in work
Egbert - 19 16v Gti, White, A/C & Leather, - Keeper
Walt - 17 TZD Turbo S, graphite, 70k miles, good op extras - Keeper
Scraper- 17 TZD Turbo E, blue, 208k miles - parts
Homer - 19 TXD E, Red, 189k miles - £250
Gary - 17 TZD Turbo E, 118k miles - in work
It seems the most common fault is the loss of the second earth to the control PCB in the cabin. Replacing the transistor module in the blower housing will not restore this, but it often gets needlessly blamed for problems! I've not been able to trace where the earth goes to (but plan to next time I have a dashboard out), however simply linking the two earths together (pin 3 will be the missing earth) seems to have no long term effects. It's only a low current from the base of the transistor it has to carry so no worries about overloading wiring.
Yes! All you need is a paperclip to bridge the connection on the PCB to the lighting circuit earth use that and hey presto, done it on 3 BX's so far and worked fine.
had a look today and compared it to the other bx and it missing the live aswell, when i earth out the the one thats supposed to be earthed and send a live down the other the fan still doesnt work and i have 2 circuit boards and there nothing wrong with either. do the relays go down on these?
1991 Citroen BX 16v - Red
1991 Citroen BX 16v - Silver
1992 Citroen BX 16v - White
1989 Peugeot 205 MI16 - Miami Blue
2002 Peugeot 406 est. HDI110 exec - Dark Blue
2006 Citroen C6 2.7HDi Exclusive - Storm Grey
Scrapped:
G650PGX 1989 ph.2 red BX 16v
G-VOT 1989 ph.1 White BX 16v
Which live do you mean? 3 and 1 are the control and lighting earths respectively, 2 is the +ve supply for the lights, 5 is the base of the transistor and 4 is from the coil of the full speed relay. This is switched to earth in the full speed position, but if you are measuring a voltage with a meter, you will see a reading on terminal 4 as there will be negligible current flowing, and hence no voltage drop over the relay coil. This won't directly be your problem, but if the relay is missing there will be no earth path from the motor to the transistor.
Best to go back to basics rather than speculate - is there a +ve supply to the motor? Does it actually turn? If you earth the motor directly and it works you've proved those two points. Assuming the motor is OK, if you quickly tap an earth connection to terminal 5 the motor should run fast. Don't do this for long, as there may be nothing to limit transistor Emitter to Base current depending on the type of board you have. If the motor doesn't spin now, either the relay is missing, the transistor module is missing its main earth, or there is a problem with the module itself. Have you read this?
the positive supply voltage to the speed control isnt there neither earths ive ruled out motor and transistor and circuit board i havent removed any relays but the wiring has been messed with in the passed im taking the dash out now to clearly see all the wiring because boxes that arent original have been plugged in for central locking and alarms ect. also the pasanger side window will go down but not come up and the door looms are fine and switches too i just think its been messed up by whoever did it i'll get pics up in a bit to show you.
1991 Citroen BX 16v - Red
1991 Citroen BX 16v - Silver
1992 Citroen BX 16v - White
1989 Peugeot 205 MI16 - Miami Blue
2002 Peugeot 406 est. HDI110 exec - Dark Blue
2006 Citroen C6 2.7HDi Exclusive - Storm Grey
Scrapped:
G650PGX 1989 ph.2 red BX 16v
G-VOT 1989 ph.1 White BX 16v
But there is no positive supply to the control PCB behind the dash (apart from terminal 2 solely for the lights), or the transistor module in the blower housing. All the speed control is done on the earth side of the circuit. Personally I think it makes sense to confirm the feed to the motor is OK, and that the motor itself works before worrying about a fault in the control side and taking the dash out.
Given that your wiring has been messed with though, a wiring fault may be likely! Best of luck, and it may be useful to post up any meter readings you get.
yeah the motor is fine the only lives are on the pcb lights and the motor, ive got the dash out and everything has been messed with haha so hours of mind bending boredom of re wiring to go!
1991 Citroen BX 16v - Red
1991 Citroen BX 16v - Silver
1992 Citroen BX 16v - White
1989 Peugeot 205 MI16 - Miami Blue
2002 Peugeot 406 est. HDI110 exec - Dark Blue
2006 Citroen C6 2.7HDi Exclusive - Storm Grey
Scrapped:
G650PGX 1989 ph.2 red BX 16v
G-VOT 1989 ph.1 White BX 16v
Have you managed to fix that faulty window? - I have seen switches that don't appear to be faulty but are & they only work one way.
The best way to track them down is to substitute them for different switches. Electronically they are all the same (front, rear or even sunroof ones).
Otherwise you can normally improvise with wires. From what I remember there are 5.
For a 1 way window the outer 2 are the motor, the middle is live & the other 2 are both neutral.
For a 2 way window the "master" is wired up the same as a 1 way with live & neutral, However the outer 2 go to where the neutrals would be on a "slave" switch, then has live in the middle & the motor on the outside.
I think the "master" is on the drivers door.
As for the auto switch, its wired up completely differently. I will go into that if need be.
Hope that helps.
1992 Citroën BX 1.9 Diesel Meteor 4x4 - The Project.
1992 Citroën BX 1.9 TXD (with GTI engine; Mulleys old car) - Parts car.
2004 Citroën Xsara Desire. (Now gone).
2016 Ford Focus Zetec - Daily Driver. (Absolute bone shaker).
Good man. Only way with a botch up. Start with the real stuff and see where that ends up. Even better it all works as half the time a chop up is a product of attempting to solve a fault from the middle rather than an end.
Miguel - 16 TRS Auto S, light blue, 43k miles - £450
Pluto - 14 E S, White, 105k Miles - in work
Egbert - 19 16v Gti, White, A/C & Leather, - Keeper
Walt - 17 TZD Turbo S, graphite, 70k miles, good op extras - Keeper
Scraper- 17 TZD Turbo E, blue, 208k miles - parts
Homer - 19 TXD E, Red, 189k miles - £250
Gary - 17 TZD Turbo E, 118k miles - in work
Just to keep this all together, I had a problem with the fan tripping in and out. Air would dribble out most of the time, but the speed control would work varying from a rat's fart to naff all. However, sometimes I would be on a hill or going over a speed bump and low and behold, the blower would come on at the full Alex Ferguson.
www.citroen.tramontana.co.hu said to check the relay clicked when connected up (which it didn't) but after piggybacking the other earth on the blower control PCB, everything magically works.
