Hi all
Have searched the forum for an answer but would just like to confirm something,
Yes my fans are permanently on when ign is on have gone through and checked everything and it seems that I have power comming from pin 10 of the a/c amplifier, should this be getting an earth at this point?

Have you checked your thermo seitch
Plugs into the passenger side if the radiator if that's faulty or not connected it will run all the time

Gatesys SW20
Have you checked your thermo seitch
Plugs into the passenger side if the radiator if that's faulty or not connected it will run all the time

Gatesy, do you mean driver's side bottom of the radiator???

Stuck my head under there quickly but couldn't see any sensor, does anyone have a pic if it? Have bridged all other sensors on the water kneel and ac pressure sensor in the fronk but No change, the problem I have found is power to pin 1,2 and 3 of the number 1 cooling fan relay and I suspect the same would be the case for relay 2 as they share the same "earth" on the coil side of the relays which in the wiring diagram I have goes to the ac pressure switch and then to pin 10 of the a/c amplifier

http://www.mr2.com/forums/mk-2-mr2-sw20/Toyota-MR2-23801-fan-always-running.html

The wiring diagram I am using is 3/4 down the page for those playing at home

redtarga. yeah sorry my bad, 

yeah there should be a sensor in your radiator, crawl under the car and its on the insed of the radiator so you have to be looking at the back of the rad, sand youll see a sensor with a round plug i think going to it, mine was unplugged due to the bad bleeding of my system, they will always run also if you have incorrectly bled the cooling system, as it will trap a pocket of air, 
stat with small stuff, check the sensor is plugged in and good, 
then re bleed system corrrectly! 

then go from there, :)

Ok will check this afternoon, thanks all for the info

Finally got around to checking the sensor in the radiator, bridged it out and fans still running, so back to terminal 10 on the ac amplifier, what I did was unplug the ac switch and then earth the wire comming from the relay to it cause the fan relays to ground, is this an indication of the amplifier transistors fried?

Not sure about your above question but i had the same issue -fans running all the time - and it turned out to be a faulty amplifier.

Yeah sorry about that, just used to having all the info, basically the coil side of fan relay 2 and 3 get ignition power and then go to the ac pressure switch and then to pin 10 of the ac amplifier which by rights should be earthed by the ac amplifier to turn the fans off