Both fans on with stone cold engine.

[Mr.E]

So I've just finished a complete service on the cooling system and everything checks out okay.

Ignition on - stone cold engine - then both fans immediately come on.
Fire her up and runs for a few seconds then revs up to 3k so switched off.

Reset the ECU even though no F's indicated, F does stay lit up though with engine running.
I thought it might be the Temp Sensor or the Earth wire on the thermostat housing but disconnected both, fans still run on cold engine reconnected and still the same.

I'm no sparky so I'm hopeful someone has the quick simple fix...

 

[NobodySpecial]

Check this out, it might be helpful.

Don't quote me, but I seem to think that this sensor (actually, two sensors in one) works by having less resistances the higher the temperature. Therefore, a short would indicate maximum temperature. Or maybe I have that backwards. :-|

 

[Mr.E]

You're spot on with Larry's last post on your link, I checked the 5v feed and nothing!
The wire has come out of the plug.
You need to be a Gynecologist to work in that area under the Injector bodies, there's no room to get in and fix the wires and they're so short so it's now Injector Body off.

I did a temporary fix with some wire on the Temp sensor and the Fans didn't come on so I think that's the problem.

 

[Igofar]

Instead of pulling the TB and risking further damage, you may want to just consider replacing the sub harness as a whole.

 

[Mr.E]

Looking at the sub harness it seems I'd still have to remove the TB's to get to the Alternator wires underneath, so I'll attempt to splice-in a 6" extension which should give a bit more wiggle room to push/pull the plug in the future.

Edit: I've had a closer look this morning and see that I don't have a sub harness, the Temp Sensor plug wires are direct from the main loom with no wires off to the Alternator.

 

[Mr.E]

That was an interesting job, managed to solder in the 3 wires and heat shrink insulate them without removing the TB's.

Only needed to buy one tool to get the 3 very short loom wires de-insulated for soldering (£6.45) and running as normal once again.

Time for a Beer!