Hello, I searched for about an hour, and couldn't find it. I'm pretty sure I remember reading about this, but here goes. I'm swapping the gauge cluster from a 91 into a 90. I noticed when the donor was fired up, the tach went to about 3500. Did the same thing when I plugged it into my truck. I think it may be a resistor on the back side of the new cluster. It's listed for 510 ohms, but it's only passing 76. Can anybody confirm/deny that resistor is the problem? Thanks, Peace, Dave.