I thought that there were only two possible fan speeds:
slow - the current supplied to the fan is limited by the resistor in circuit thus reducing speed
fast - battery voltage applied directly across fans (no resistors in circuit)
As you have a bridged resistor that doesn't make sense!
I understand that the slow speed is actually variable, as the resistance of the resistor on the radiator varies with temp - as temp increases resistance reduces so fan speeds up as it gets hotter to give more cooling. Maybe there is a separate resistor (back with the relays?) to control the max slow speed, hence when you bridge resistor it goes to the max slow speed, rather than fast.
That would make sense, but it could be nonsense - anyone any idea?
Does it behave the same with aircon on - that should hold temp more stable around 90deg, so cause slow fans to cut in around then? If no different to a/c off (i.e. only get fans at 105deg still) I would start to suspect lack of effective cooling rather than dodgy sensor - as slow fans should cut in around 90 when the a/c gas pressure hits trigger point - regardless of water temp. So would start to consider if radiator needs replacing or if you havent had original plastic impeller water pump replaced could be that is on the way out...
So just need to figue out where the ecu temp sensor is.
from my last post:
I think one sits next to the thermostat housing (so if you're getting a new stat fitted, easy to change at same time), the other I have been told is fitted somewhere near the (lower?) coils / injectors - so would need the cover to left of the oil filler cap taking off to find. No idea which drives gauge and which ecu, but certain other threads have this info
...and I think 156Chris said that it is the one on the 'stat.