Okay, really odd question, I haven't started my car in about 2 months (installed a bunch of new parts, etc.) and long story short I'm having an issue with the coolant gauge reading very high. I need to find out of this is a problem with the gauge cluster or something like the thermostat. When I first started on my car I opened up my gauge cluster completely down to the circuit board and put it all back together in an attempt to install a wideband gauge in the blank spot. My suspicion is that the temp needle some how was not installed again correctly or was moved off position.

So my question to help narrow this down, when your car is cold and you get in it, you turn your key to the ACC position, what does the needle on the temp gauge do? And what does it do if the car is hot?

For example, I know for a fact when you turn the car to ACC, the fuel needle moves to the correct position of how much fuel you have. Does the temp gauge do something similar? Does it do a startup movement where it will go to 1/2 or H and then fall back down again? Or go to where the temp is just like the fuel? Etc.

 

Hot or cold, the temp needle shows real temp without a sweep, it just moves to its appropriate position on the gauge and stays there when the key is moved to ACC position, just like fuel.

 

quoting to reinforce this. no startup sequence like an STI has with the gauges sweeping

 

The temperature sensor grounds through the engine block which grounds to the battery. After whatever work you were doing, did you get all the grounds reconnected?