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        General >> Problems >> Cooling fans not working
        
(Message started by: adowds on Apr 9^th, 2007, 9:04pm)

Title: Cooling fans not working
Post by adowds on Apr 9^th, 2007, 9:04pm

Hey lads,

Having troubles with the 24v's cooling fans. They don't come on by themselves at all, giving hot running in traffic. I've spent today fiddling, but not got very far. The relay seems fine, as are fuses and the fan.

If I put a wire across the two pairs of big connectors on the relay plug, the fans come on one at a time. And there is one 12v feed across pins 7 and 8 on the relay connector. When I put 12v across these pins on the relay, it clicks and closes the connection between the two pairs of large connectors.

Should I have 12v between 7 and 9 on the relay when the ECU wants the fans to come on?

My AC isn't working either, so the fans don't do the slow speed turning either.

I also metered the ECT sensor and it seemed to be working okay.

Hmmm...

Title: Re: Cooling fans not working
Post by sector-9 on Apr 9^th, 2007, 11:18pm

The relay coils have +12V to them when the ignition is on - the ECU switches the ground returns to actuate each relay. One of the large terminals should have +12V to it at all times, another should be permanently grounded, and the remaining two connect to a fan motor each. Before testing for voltages at the relay socket you should disconnect both fan plugs otherwise you'll get erroneous readings. From memory there are four smaller terminals which have ign. switched +12V, permanent ground and two switched grounds for the two fan speeds.

Darren

Title: Re: Cooling fans not working
Post by adowds on Apr 10^th, 2007, 12:28am

Aha, right. Never thought to disconnect the fans.

There are only three small terminals, 7,8, and 9. 7 is ground, 8 has +12v switched with ignition. 9 had nothing when I metered it initially, then it gave +12v, then stopped again later.

A new ECT is only £12 and the old one looks a bit creaky, so will change that anyway. After that it can only be wiring I guess.

A temporary bypass wire and switch will keep me mobile while I keep trying I guess!

Title: Re: Cooling fans not working
Post by scorpio_man on Apr 10^th, 2007, 8:51am

hi there

you've seen this (http://www.fordscorpio.co.uk/coolfans.htm), if it's any help.

re the wiring. also have a look at the loom connector 'boxes'. the ones with the 10mm? nut on top. they can get a bit messy with ps fluid and dirt.

hth

Title: Re: Cooling fans not working
Post by sector-9 on Apr 12^th, 2007, 5:59pm

I never understood the logic of Ford wiring the fans up to run all the time the A/C is on. Sure it makes sense if the car is stopped, but when you're doing 70mph down the motorway then it's rather pointless!

I 'doctored' the wiring on mine so that the fans only run on low speed as the A/C pressure rises (note that this is before it rises enough to shut off the compressor) - however I may need to make it run on high speed when the pressure rises as on low speed alone it doesn't seem to cool the condenser quick enough and the compressor still stops after a few seconds...

Darren