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Topic: Cooling Fans not working - help please (Read 834 times) |
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DazRSK
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Cooling Fans not working - help please
« on: Nov 30th, 2006, 6:08pm » |
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I need to lean on some experience / knowledge / guidance from you guys please. How much do you know about the wiring for the 2 cooling fans on the diesel Scorpio - the one with the 3 way thermal switch ?
What's happened - well, the cooling fans do not operate at all. I have no slow running fans when the climate / aircon is running and I have no fast running fans when the coolant/engine temperature rises above normal. This latter situation was the first to lead me to believe something was wrong the other morning whilst stuck in a jam on the motorway. Yes - I had a new warning light glowing on the dash for the 1st time - I have never seen the red thermometer light before. Which leads me to believe something recent has malfunctioned.
What I have checked -
Plugging 12V and earth direct from batery into both fans does make them work - not a fan fault.
Checking all 3 fuses in the battery side box - 37, 39, 44 - proved that none had blown - not a fuse fault.
Jamming a piece of wire into 2 terminals in the thermal switch multiblock does not make the fans work with ignition on - probably not a thermal switch fault.
I have a permanent live wire at the driver's side fan, but no live at the passenger side - with/without ignition.
So I am now a bit stuck. I may have to rewire the whole thing but I am struggling with the relay and how each fan speed cuts in but is separate - ie one speed for aircon and faster speed as a cooler.
Placing circuit tester on wires into relay (while connected), I have 3 twin coloured thick wires and a thick black wire (earth?). 2 of the twin coloureds are permanent live, but I cannot get anything from the top wire into the relay - which I think is brown/yellow - sorry, this is where I really need to be next to the car. There is an ignition switch smaller wire (aircon ?) going into the relay. Then there are 3 more little wires feeding into relay - none are live.
Is the thermal switch an "earth" switch or should there be some current on one of the terminals ? If anyone can advise on how the thermal switch is wired, that would be a good start.
It would be nice to rewire it the way Ford originally did, but short of any wiring diagram, the best I can do currently is rewire it so that the fans run permanently on ignition switch.
Yes - I could strip off all the insulation tape but it looks like a dog's dinner of a loom.
Has anyone got any ideas please ?
Thanks.
Daren.
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scorpio_man
Administrator
Ford Kuga awd
Posts: 5654
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Re: Cooling Fans not working - help please
« Reply #1 on: Nov 30th, 2006, 8:23pm » |
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hi there
on the main site is this
and all the wiring is here
does this help any?
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DazRSK
Junior Member
I'm a YaBB newbie!
Posts: 95
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Re: Cooling Fans not working - help please
« Reply #2 on: Dec 1st, 2006, 2:17pm » |
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Scorpio-man - thanks for this. I think the wiring diagram on the attached link might actually do the trick.
Thanks for your assistance on this - this is extremely helpful.
Daren
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Snoopy
Administrator
Very old.BAD tempered and missing friends.
Posts: 6278
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Re: Cooling Fans not working - help please
« Reply #3 on: Dec 1st, 2006, 5:56pm » |
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There is one guy on here who has done some modifications to the fans on HIS TD scorpio .... if I can find his posts about it I will let you know ....
Its Sector-9 and Iam ATM unable to find his posts with regards this .
try doing a search yourself sometime around May of this year
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pappa
Full Member
VM Diesel 2.5Tdi 90kW
Posts: 259
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Re: Cooling Fans not working - help please
« Reply #4 on: Jan 17th, 2007, 6:47pm » |
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Hi Guys!
I have the same problem in 24V. My cooling fans are not working.
- Climate control on = both fans on low speed.
- The needle in the instrument panel NEVER rises above HALF
temp, unless I connect it directly into GROUND. Then it will go
up, but fans stay silent. 
- OBDII tells me that the engine is getting hotter and hotter
when running it idle
- Tried tapping the relay a few times, no help, removed it and
checked the multiplug - nice and clean...
- Also have a stalling problem, if idling for a while, engine idles
beautifully and then starts swaying, revs go up & down and then
stalls.
- Thermostat has been changed a while ago, unfortunately local
Ford did not bother to change an old hose and it started to bleed.
This brought the Fans not working to my attention, steam hissing
out from the hole in the hose 
Phew... just when I thought I was slowly getting closer to the
end of monthly repairing of the car that has gone on for almost one
year now  I'm crazy, I should sell it
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My cars are the best and the pigs and cows fly.
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sector-9
Senior Member
No scorpio anymore
Posts: 1069
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Re: Cooling Fans not working - help please
« Reply #5 on: Jan 18th, 2007, 10:50pm » |
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Don't know if Daz got the fans fixed but on mine it turned out to be the wiring loom where it passes in front of the radiator (clipped to the front cross-member behind the bumper) - on the driver's side it had gone brittle and the conductors had all but failed (as had the insulation which I discovered when it started sparking and smoking after I moved the loom  ). This loom also contains the wires for the EGR vacuum regulator solenoid which caused a whole load of other problems when it died...
Anyways, you need to pull out the big green relay, which is probably knocking around behind the RH headlamp, and use a multimeter on the four big terminals in the socket. It's been a while since I've worked on them but from memory one terminal is ground (earth), another is permanent live (+12V) and the remaining two both go to one fan each. One fan should have a permanent live to it already, and the other should have a ground connection so you can make either run at full speed by supplying it's missing connection (either ground or +12V as appropriate), or both run at half speed by joining their free ends together - if that makes sense? Basically the relay changes them between being wired in parallel (high speed) or in series (low speed); in high speed mode the relay has to provide both ground and live to the fans, in low speed mode it just joins them together - that's why it's possible for one fan to continue working on high speed if the other fails, but neither will work on low.
The relay itself is unlikely to fail unless it is visibly damaged or full of water - which relays close or open depends on whether one or both inputs (from the radiator switch or ECU) are grounded. Finally there is an ignition switched feed to the other side of the relay coils to ensure that they all open and cut the fans when you turn off at the key, and a thin ground wire for the relays to work.
Darren
P.S.
Specific answer to Daz: The radiator switch is two separate switches in a single unit, both of them switch ground connections to the green relay depending on the water temperature and one of the ground connections is also switched by the pressure switch on top of the air-con receiver. You can alter what speed the fans run at when the air-con is on by changing which ground wire to the relay the pressure switch is spliced into. On some models it was accidentally connected to the *input* side of the pressure switch so the fans ran continually whenever the air-con was turned on - even when doing 70mph on the motorway  BTW, check the direction of rotation on both your fans - Ford issued a TSB because on some early models one of the fans had been wired backwards! 
Specific answer to papa: If both cooling fans run when the climate control is on then your problem is not likely to be the fans, relay or wiring - it's most likely the ECU is not switching the relay on. It would be worth you checking the engine coolant temp sensor as this could also cause your stalling problem at idle if it thinks the engine is colder than it is (and therefore running too rich), though your OBD readings would suggest this is also working fine - perhaps just trapped air in the system?
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pappa
Full Member
VM Diesel 2.5Tdi 90kW
Posts: 259
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Re: Cooling Fans not working - help please
« Reply #6 on: Jan 19th, 2007, 7:34am » |
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Thanks, a very good description! I'll start working on them a.s.a.p.
Thank you, I'll post my findings.
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DazRSK
Junior Member
I'm a YaBB newbie!
Posts: 95
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Re: Cooling Fans not working - help please
« Reply #7 on: Jan 22nd, 2007, 2:25pm » |
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I haven't looked through the Problem page for a while - so have only just come across this.
In answer - yes I did fix these in the end. Turned out to be the 3 way switch and I didn't have the bottle to take it out of the rad, for fear of causing further issues to a 12 yr old rad.
I took a more rudimentary approach of making a permanent connection across the 2 of the terminal in the multiplug which connects to the switch - this means that the fans rotate on slow speed continuously. I have also fed some wire back into the car from the other terminals and made a switch up for the faster speed.
A bit crude but cheap and does do the job.
Pappa -with the 24V though, you don't have the same issue as me due having a more electronic (technical) version to control the fans, instead of the simple (perhaps, more temperamental) switch.
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DazRSK
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Posts: 95
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Re: Cooling Fans not working - help please
« Reply #8 on: Jan 22nd, 2007, 3:02pm » |
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Actually, once I completed the job of fixing these in November, I was going to post up a crude how to..... . It took me a while to suss out exactly what went wrong with mine and, as with any electrical job, it's always a process of elimination. For an expert who works on these regularly, obviously, 2nd nature takes over. However, for me and probably a few others on here, I had to work it all through.
OK, first - these will only apply if you have a 12V 2.9 or a 2.5TD - the other versions have a more electronic control and do not have the 3 way switch in the rad.
The problem areas - you've got 3 fuses in the battery side box - one for the relay and 1 each for each fan. The other areas is to ensure are OK is the relay, the fans, wiring loom and the rad switch.
I won't go through a very detailled how to - but what you need to check is:
- the 3 fuses are OK ?
- by directly connecting fans up to the battery, do they rotate ?
- Does the driver's side fan have a permanent live and are the earth leads on both fans actually grounded.
- Once all of this is established, you need to check the big green relay behind driver's h/lamp with a multimeter to ensure that earths and lives are OK. I even connected up a few live wires together, with the relay out of its housing, to see if the fans work.
- If this is OK, the switch in the rad is most likely the prob - fix a wire across these terminals to see if fans now work.
- If nothing still works - you may need a mutimeter to check the loom.
Very crude & very simple - but this should eliminate any probs if the fans don't work. Don't forget - on these Scorps, both fans should work or none at all.
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