There are two different switches on your thermostst housing, both are for coolant temp management.
1. The 2-wire switch is only there to turn your fan on at ~210 deg.
2. The 1-wire switch turns on your light on somewhere around 230 degrees (not sure of the exact temp) by supplying the ground to the light bulb.
There are two possible causes for your light to come on prematurily and both are caused by the 1-wire switch.
1. the switch took a dump or
2. there is another source of ground at the switch that is making it come on. Most times water will create a path to ground but usually will only allow the light to come on dim.
From what you describe, it sounds like you you have a bad (1-wire) switch.

Hope this helps

 

Got it guys........thanks! found 2 things that might have caused the problem.
1 wire switch had a intermittent lead about 2"up...........not sure how that happend.
Also found that I wasnt pumping water to good. Some kind of air bubble somewhere I think. I looked at coolant flow and it wasnt goin' worth a hoot. Drained and refilled and no problem? go figure


Thanks for all the help guys. Looks like Glamis is on for next weekend!