Left Fan not coming on

[Dischordant]

Hi guys - left cooling fan at the front isn't coming on - I think it's meant to come on at the lower temperature. The other fan does come on when the coolant temperature hits about 100. I've tried switching the fan connection over and the left fan then comes on but not the right. I assume this means that the sensor is working but that maybe the connection is corroded. I want to test this with a voltmeter/rewire but it is annoying to need to get the engine that hot each time. I read how if I disconnect the sensor it will automatically turn both fans on but unfortunately I cannot find the connection/sensor they use.

Is anyone able to show an image/explain how I find the sensor that I need to disconnect which will cause both fans to turn on?

Many thanks for any help! - would prefer to fix it myself if it's just soldering on a new plug instead of taking it all the way to Oxford for what could be potentially an easy fix!

Darren

[R7EBO]

Probably a daft question but have you tried swapping the relays over in the drivers' footwell? I had a problem with mine which turned out to be a knackered relay. It's the 2 yellow ones IIRC. Also plugged mine in & when it was showing 96 degrees on the dash, the software said it was only 88 degrees and thus no fans running when I thought they should've been.

[NCE 61]

The ECU coolant temperature sensor is under throttle body No5:-



Could also be the relay or fuse.

[Dischordant]

Apologies for my ignorance but what is the difference between a relay and a fuse?

I checked the fuses that I think are linked to the fans http://www.mytuscan.co.uk/downloads/fuselayout.jpg (the top left and near top right ones) but they were fine as far as I could tell (replaced with new in case).

I don't know where the relays are located (are they 23 and 51 located on the same fuse board?)

In the awesome photo above is throttle body 5 the one nearest the left or the right of the engine in the photo? Again sorry I don't know these things! =)

Thanks guys - you're brill!!

Edited by Dischordant on Wednesday 19th November 15:09

[NCE 61]

Relays are 23 & 51:-

http://www.mytuscan.co.uk/downloads/fuselayout.jpg

Throttle body No5 is the fifth one from the front of the engine.

[Dischordant]

Thanks! =)

Switching relays made no difference (only higher temp right fan came on at 100degrees) so relays must be fine.

Will take off the bonnet tomorrow when I have a bit more daylight to spare, disconnect the sensor and check the voltage where the fans plug in - I'm assuming it might be an eroded connector. If so - would I have any luck trying to clean it up with wire wool or better to solder on a new connector?

Cheers!

Darren

[OutlawFlat4]

I had the same issue a few weeks back with my AJP and it was caused by crappy wiring into the connectors.

The fans should Fire up when the engine is on and the temp sensor disconnected so try this first to discount a more complicated issue but my guess is it's the connector. Don't try and clean them as they are only a few pounds to repace and can even be crimped vs soldered so nice and quick.

[Dischordant]

Thanks Outlaw - where can I pick them up? Tried searching but didn't have much luck =/

[nawarne]

Dischordant said:

Thanks Outlaw - where can I pick them up? Tried searching but didn't have much luck =/

Main bonnet off.

Look at "frontmost" chassis cross member square section (fans immediately in front). Loom is zip tied to this steel. Connectors to fans are large 2-pin plastic spade connectors. It's a case of lifting them up and opening, then spray some contact cleaner on metal conductors. Get some vaseline on the connectors.

If one fan is coming on, it is not because of "ZERO" signal from ecu due to failed water temp sensor.

Unplugging the ecu water temp sensor will cause both fans to come on (engine running) - so good way to check relays/fuses/wiring/connectors.
Nick

[Dischordant]

I think it must be the wiring - I tried trimming off the connector and voltage testing the wires and nothing coming through. Think I'm going to have to take it in =/ At least I checked everything I feel able to! Thank you for all your help!