Micro,

I have almost always found that when something changes drastically, it was the last thing you did that caused the problem.

Since doing something to the instrunent panel shouldn't ever affect the running temperature of the engine, it is likely that you did something to change the temperture gage. Possibly an open ground circuit a or a stray voltage is getting to the gage. This is most likely the problem since the engine doesn't "feel" hot to you.

I'm assuming that you have an electrical temperature gauge since you didn't mention the model. Also, what is the time line between replacing the IP and soldering the light potentiometer?

P E H