Temperature light flashing.

[BigVasey]

Seems like I have a bad connection in the wiring for the temp gauge and light on the dash. With the ignition on but not running, I can shake the large connector under the hood and the light for high temp flashes off and on. It also does this while driving. Most of the time it reads a normal temperature but when the light comes on the temp gauge also pegs out. Anybody know what color wire in the large connector runs the temp gauge and dummy light? I have checked both sending units and they appear fine. No loose connections.