Hi
1998 406 V6 (ES9J4) saloon
I think my n/s cooling fan is dead. Symptoms are that only the o/s fan ever comes on at ~90deg (fast speed, parallel mode), neither fan comes on at the lower speed (serial mode). I have pulled out the relays and tested them all working, middle one had corroded contacts which I've sanded shiny but no joy. Checked the 4x50A fuses all OK. Therefore suspect the fan itself is dead (open circuit).
Both fans 'feel' fairly free and easy when I spin them by hand so it's not seized.
Now I've read a couple of threads about this which suggest you can get to the nuts from behind by unclipping and moving the rad / condenser back enough to get clearance? Can anyone give me more clues... I have so far got the badge grille thing off (in order to see the relays). The stuff I've read implies there's just clips to undo to move the rad etc but all I can find is two clips at the top which just seem to hold the rad to the a/c condenser - undoing these allow the rad to bend back a bit but the condenser is still in the way. I can't figure out how the condenser is held in place. Doesn't really look likely that even if I could move both back a bit that there'd be enough space?
Looks possible that removing the bit the bonnet catches are attached to might help. Is that what's called the 'slam panel'? Someone mentioned they took that off but it didn't help but I'm not sure what exactly they're referring to.
I'm a bit of an amateur mechanically but ok on electronic side so fairly confident if I can get the motor off and have it apart it may just be brushes worn out?
Confused - can anyone help!
Thanks
Justin
406 V6 Cooling fans ... how the ....?
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Hi Justin,
Welcome to the forum
You diagnosis is good but do check the relays and more importantly the relay bases for signs of overheating and burning before condemning the fan. The relays pass a high current and often develop high-resistance connections that lead to localised overheating and burns on the relay bases.
If it is the fan itself, it can often be provoked into temporary life by poking the blades with a stick and giving it a helping hand. It's usually down to the brushes being worn out. If you can make it run like this, you may see it windmill much more freely when power is removed that the good one.
I cannot speak directly of the 406 V6 but of the Xantia V6 I can and I expect things are very similar...
You should be able to get at the fan nuts from the grille without needing to touch the rad or the condenser but what you need is a very slim 10mm socket that will squeeze between the fan securing nuts and the condenser. Us Citroen owners use a small 10mm socket by grinding flats on it so it could be turned using a spanner. Then the fan motor will hopefully just about slip off but you'll need to remove the blades first. Note that the screw holding the blades to the motor has a LEFT-HAND thread just to confuse.
Fans are a mighty problem and there has been a ton of posts in the Citroen area of the forum. Look especially for posts by Clogzz as he is our resident cooling guru
If need be, I can supply a typical circuit of the fan arrangements if your search of the Citroen forum does not unearth one.
Hope that helps Justin....
Welcome to the forum
You diagnosis is good but do check the relays and more importantly the relay bases for signs of overheating and burning before condemning the fan. The relays pass a high current and often develop high-resistance connections that lead to localised overheating and burns on the relay bases.
If it is the fan itself, it can often be provoked into temporary life by poking the blades with a stick and giving it a helping hand. It's usually down to the brushes being worn out. If you can make it run like this, you may see it windmill much more freely when power is removed that the good one.
I cannot speak directly of the 406 V6 but of the Xantia V6 I can and I expect things are very similar...
You should be able to get at the fan nuts from the grille without needing to touch the rad or the condenser but what you need is a very slim 10mm socket that will squeeze between the fan securing nuts and the condenser. Us Citroen owners use a small 10mm socket by grinding flats on it so it could be turned using a spanner. Then the fan motor will hopefully just about slip off but you'll need to remove the blades first. Note that the screw holding the blades to the motor has a LEFT-HAND thread just to confuse.
Fans are a mighty problem and there has been a ton of posts in the Citroen area of the forum. Look especially for posts by Clogzz as he is our resident cooling guru
If need be, I can supply a typical circuit of the fan arrangements if your search of the Citroen forum does not unearth one.
Hope that helps Justin....
Jim
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Thanks, Jim
I think a penny has just dropped - we're talking accessing the nuts at the back of the fan by reaching in from the front aren't we? I think the whole rad / condenser thing confused me into thinking people had found a way to get in from the back without removing the rad.
Will have a poke about at the relay bases before I go into surgery mode - one of them is corroded for sure but didn't look too bad. Hopefully with the aid of a multimeter it should be possible to figure out which connections feed the fans and feed them 12v direct to test... that's the theory at least.
Shame also the blades can't be undone from the front - that would make things a lot less fiddly.
Cheers
Justin
I think a penny has just dropped - we're talking accessing the nuts at the back of the fan by reaching in from the front aren't we? I think the whole rad / condenser thing confused me into thinking people had found a way to get in from the back without removing the rad.
Will have a poke about at the relay bases before I go into surgery mode - one of them is corroded for sure but didn't look too bad. Hopefully with the aid of a multimeter it should be possible to figure out which connections feed the fans and feed them 12v direct to test... that's the theory at least.
Shame also the blades can't be undone from the front - that would make things a lot less fiddly.
Cheers
Justin
Hello!
Just thought I'd report back...
Went down this evening with a multimeter, 12v sealed lead-acid battery, some bits of wire and some circuit diagrams off one of the excellent threads on here.
Firstly I prodded stuff with the meter and couldn't make much sense of owt.
The relays on the 406 seem to be a different way round to some of the pics I saw - the changeover relay is top right looking from the front (you can tell as it's the only one that has a spade connector to both throws of the relay).
Tried feeding some volts to the fans using my understanding of the circuit diagrams and the external battery. No joy. I think, however, this was because I was back-to-front in my readings of 'left' and 'right' being looking towards the front of the car in all the circuit diagrams rather than as you would look at the fans from the front.
Anyway eventually puzzled a bit then tried shorting some pins (all relays out). Pins 3&5 shorted on the left hand (in picture) relay made the left-hand (offside) fan run full speed. Same on other relay no effect. Then I put the changeover relay back in, tried shorting 3&5 on the middle relay and ... both fans low speed ... WOOOOO!
Chucked all the relays back in, started it, ran up and down road, sat it for 10 min or so, CLICK, fans on slow speed! Yay!
The only thing I did in the end was to clean up the contacts on all the relays (and swap them around, incidentally they're all identical on the 406). Ad you can probably just see in the pic the middle relay (nearside fan relay) had a bit of corrosion. Could just have been that causing the problem? I may never know. Also could possibly be related to damp - the car had been sitting for a while and got a bit damp - had some other indicator alarm flashy weirdness that seems to have stopped after a bit of warming through.
Anyway, thanks you, Jim, for your reply and to all the other posters on previous threads who had been so helpful.
And thank feck I don't have to get that fan off - I can see how your method would work but actually trying it I can't even begin to see how you manage to do it pushing your fingers between fan blades - I can barely reach the top (easiest) nut with my fingers let alone getting a socket / spanner back there and turning it.
Oh and my other thought had been if I had had one fan open circuit was to wire the relays such that the other one came on full speed at the low-speed setting. That would at least have stopped the engine having to get up to the higher temp before getting any cooling in traffic... a bodge it would have been but I simply can't see how anyone has fingers small enough to get those fans off!
Well anyway will take it for a longer run tomorrow and fingers crossed it will keep on working!
Cheers
Justin
Just thought I'd report back...
Went down this evening with a multimeter, 12v sealed lead-acid battery, some bits of wire and some circuit diagrams off one of the excellent threads on here.
Firstly I prodded stuff with the meter and couldn't make much sense of owt.
The relays on the 406 seem to be a different way round to some of the pics I saw - the changeover relay is top right looking from the front (you can tell as it's the only one that has a spade connector to both throws of the relay).
Tried feeding some volts to the fans using my understanding of the circuit diagrams and the external battery. No joy. I think, however, this was because I was back-to-front in my readings of 'left' and 'right' being looking towards the front of the car in all the circuit diagrams rather than as you would look at the fans from the front.
Anyway eventually puzzled a bit then tried shorting some pins (all relays out). Pins 3&5 shorted on the left hand (in picture) relay made the left-hand (offside) fan run full speed. Same on other relay no effect. Then I put the changeover relay back in, tried shorting 3&5 on the middle relay and ... both fans low speed ... WOOOOO!
Chucked all the relays back in, started it, ran up and down road, sat it for 10 min or so, CLICK, fans on slow speed! Yay!
The only thing I did in the end was to clean up the contacts on all the relays (and swap them around, incidentally they're all identical on the 406). Ad you can probably just see in the pic the middle relay (nearside fan relay) had a bit of corrosion. Could just have been that causing the problem? I may never know. Also could possibly be related to damp - the car had been sitting for a while and got a bit damp - had some other indicator alarm flashy weirdness that seems to have stopped after a bit of warming through.
Anyway, thanks you, Jim, for your reply and to all the other posters on previous threads who had been so helpful.
And thank feck I don't have to get that fan off - I can see how your method would work but actually trying it I can't even begin to see how you manage to do it pushing your fingers between fan blades - I can barely reach the top (easiest) nut with my fingers let alone getting a socket / spanner back there and turning it.
Oh and my other thought had been if I had had one fan open circuit was to wire the relays such that the other one came on full speed at the low-speed setting. That would at least have stopped the engine having to get up to the higher temp before getting any cooling in traffic... a bodge it would have been but I simply can't see how anyone has fingers small enough to get those fans off!
Well anyway will take it for a longer run tomorrow and fingers crossed it will keep on working!
Cheers
Justin