flashin water light on my caddy???

hi there peeps.....i need to know where i run the wire from to stop my water temp guage hitting the pin at the top, and the light flashing............

i have jsut fitted a GTD lump in my mk1 caddy, and the mk1 diesel loom i've fitted, doesnt seem to have a wire that runs the temp guage (or i have it in the worng place)

Im running an early type loom, with the single pin connector on the water flange on front of head...... Im guessing this is where i need to connect the wore to...but what colour is it, does any1 know?? Need to get the temp guage working so i can at least check she's not running hot and check fan is working etc??

please help!!!!!