Help coolant temp sender driving me nuts!

The coolant temp gauge in my rado is behaving strangely, sometimes on start up the red light flashes as it should, but then it doesn't go off when the engine is upto temp, when this happens the temp gauge doesn't read. And then the other day i turned it on and gauge worked fine but no light flashing when cold? Went back to the car yesterday switched it on, red light flashing no temp gauge. Everything looks fine and dandy but i do have a spare blue and white wire in the same region as the senders spare, but know where to put it? The car is a 91 16v corrado, but its got a abf engine. So firstly were is the coolant temp sender on the abf (pic with big arrow would be nice!), i think its on the side of the block but exactly where? Also what colour wire should be going to the sender? I've cross referenced vr6 corrado, mk3 and mk2 golf wiring schematics, but as of yet not a 16v corrado one, i just assume its the as the vr6 corrado. At first i thought i it was a loose connection now i'mleaning torwards a dodgy sender. Help plz i'm loosing my will with it now!

Thanks
Greg

silly question have you checked the coolant level?

Nice to see someone thinking outside the box. I think it may be to do with the fact i haven't got the right thermo-switch and fan wiring setup. When i bought the car it had a 2-pin thermoswitch and its supposed to be three pin, the red and brown wires from the loom went to there respective positions but the white/red wire had been cut off short and taped up, so in the process of returning it back to the way it should originally be. I'll be fitting a new thermo-switch and changing the coolant in the week, hopefully that will cure it otherwise i can only think that its a faulty temp sender.

well i have two different spare temp sensors if it you identify it is the sensor i can post for a few pounds. Pm guy on here he would be the person to help you if anyone can.

Thanks for the offer mate, i got a brand new one from vw though. I think i know what the problem is, or at least where to be checking now if there was a 16v corrado wiring diagram out there though i'd be more confident. As it is i'm crossing referencing between, golf mk2/3, and corrado vr6 ones and seeing which is the most similar to what i've got.

Thanks
Greg