I have a problem with the guage not registering the placement of the trim. It is pegged to the top of the guage most of the time. When you try to adjust it will move a little, but once you let off it will peg back up. Just a few weeks ago I was moving along and looked to find the guage reading correctly, but the next time out it was back to the top. What is wrong with this thing? I have pulled the guage to check for shorting, but all wires look new. Please help