I've been having some odd cooling issues with my truck lately, the temp gauge on the dash likes to go from cold to op temp, then back to cold again. Sometimes hovering in between. It never reads hot, so I'm not concerned about overheating, but I wonder if either the connection on the dash is loose or the sensor itself is shot. I have an aftermarket water temp gauge on my pillar and I would love to wire it up, but I'm not sure which of the 2 sensors is for the dash. One is gray, one is brown. I haven't had much luck figuring out which is which. Any ideas? Thanks!