temp warning light
Hi,
This circuit is pretty basic. Are you sure you don't have an overheat situation? I think the switch is set to close above 250 degrees F. It's quite possible that you have a low coolant level , maybe air in the system, after replacing the thermostat. If that is not the case, I hate to suggest it, but you did install the stat with guts inward toward the intake, right. I don't even know if it's possible to mess that one up, but I had to ask.
As far as the light circuit is concerned,the hot light goes on with a ground through the switch, only other time it should light is during bulb test, between run and start with the key.Anything else, we're talking short to ground, in the engine harness wiring, hopefully.
I guess that's it. Since apparently you had no light until the tstat change, I really think you have a hot engine. If you are in doubt, change the coolant temp switch. Be precise when you ask for the part, don't get the coolant temp sensor or high speed fan switch! Good luck!
