getting my fan working

[tim]

I want to get my fan up and running on the Red One (19 TXD). Last year I checked out the system and there wasn't any power getting to the fan which otherwise works fine; so I rigged up a simple flick switch into the dashboard so the wife or myself could turn it on during hot spells. However, automatic is better so I am going to need a relay and a sensible wiring plan to rerig it. So - what relay? Surely it doesn't need to be a Citroen type, any cheap generic type would do..... as for wiring, I do have the Book but it's very difficult to work out in that rat's nest what is exclusive to the fan; a quick hand-drawn sketch would make more sense to use and follow! A guess, power into relay, earth out, leads to fan and rad sensor etc. but as the car didn't come with anything fitted I'm guessing. The car got too hot last year in a traffic block on the M3 so the fan IS needed occasionally. The White One also has a similar need; the fan stopped working a couple of years ago. Also, my daughter blew up her Seat Ibiza on the A303 last night due to a lack of fan - which concentrates the mind. On that note, hello to the silver BX16 estate parked on a back road in Gill town centre, Dorset....

[David]

Have you tried replacing the fan switch in the radiator to fix the problem?

Originally the fan relay is in the interior fuse box, from there a live wire goes to the switch & resistor (sorry, I can't remember in what order), then to the fan. from what I remember, the resistor has 3 wires & the switch has 3 wires. 2 that go from the switch go to the resistor & the 3rd is ether the incoming or outgoing live to the actual fan. (again I can't remember which way its actually wired).

Surely you can test the wires & get the original setup working again.

EDIT: this is only for the single fan models, I don't know how the duel fan models are wired up.

Hope that helps.

[tim]

David - hi. Thanks for that. The rad switch is a fairly recent replacement so should be OK. I am trying the simplest fix which is to fit a new relay, the rest is just simple wiring. But I would appreciate it if anyone can provide a fag-packet drawing of the circuit needed for this set-up without any extra non-fan gubbins. It doesn't help that half the wires are the same colour! Obviously finding the live feed is no problem, and in case the issue is within the fuse box I will run a separate fuse into the wiring until I know it all works.

[Tinkley]

Mmmmm, this sounds familiar. I had the a similar problem in that the warning (over heating water) light coming on with 1.6 petrol. On investigation I had 1. A seized fan. 2, Blown fuse on Circuit 4 (cooling) and 3. Knackered thermostat switch on the radiator. Warning! do not poke fan blade with fingers with hot engine and battery connected....

As it happens the latter has just gone again. The relay seems solid but check all the rest of the system. It is possible to short the thermostat switch quite easily, with a wire loop. Make sure if you do replace the thermostat switch it is correct (range) for your engine as there are different temperature ones specific to different engines.

[tim]

I checked the fuse a while back, seems OK. However, as I said previously, the simplest way is to buy a new £2 relay unit (especially if the original is buried in the fuse box somewhere!) and wire it up to the fan. The thermostat is nearly new and seems to be fine, but as there is no power available to the fan in the existing setup I need to choose a new 12v feed and splice in a separate fuse (easy) then see if it works. As the fan is OK it should do. I just need that fag packet diagram,chaps! I have an old mk 2 fusebox so I'll check to see if I can find the relay on it.

[tim]

To add to that - I checked the spare fusebox and the relay is a green one. It may well supply power but where the feed wire is for the fan is a mystery given how the loom has been hacked about; the car was fitted with two fans up to last year with a hand-built linkage to them, but they never worked and I have now removed one altogether. If I am reading it right the diagram shows power into the fan (brown wire) via the fuse and what may be a switch or owt, ideas please, then down to the resistor and the relay.

[tim]

and again.... I suspect the resistor has fried as well, and there isn't a rating in the book that I can find. Can someone give me a grading for it so I can order another from the local motor factor?

[Way2go]

You seem to be getting your feeds mixed up with your switches. The fan is switched by the temperature sensor in the earth line, There are 2 stages of switching, 1 via the resistor from the fan (Slow)and 2 (Fast) direct from the fan.

If you short all 3 pins of the sensor that will switch the fan on high speed and the resistor will not stop the fans working for this test.

However on the feed side, the fuse must be good and the relay must be enabled by energising from ignition on to give you 12v at the OTHER side of the fan.

I think it is unwise to install duplicate relays and wiring as this could create a hazard without isolation of the original fitments. Far better to repair the original feed route if that is defective as any later owners will not necessarily be aware of such bodges introduced. Always best to keep it simple!

The BX can get hot in crawling traffic and for this reason if you want to install a relay to bridge the fast contacts of the thermo switch, this could be controlled from the dashboard or console mounted switch to give continuous cooling when in these situations. (My factory air-con needs charging but switching this on in slow traffic still brings the fans on and a benefit is seen on the temperature gauge.)

Hope this helps.