I have autometer pyrometer and trans temp gauges and when I run the fan, turn signals, etc, the gauges go crazy....needles bouncing all over. Any ideas how to cure this? BTW, the factory gauges are working fine and dont bounce around like my aftermarket ones.

 

Where did you ground your gauges?

 

The gauges are grounded at a metal bracket under the dash.

 

I had the same problem run the ground out to the engine or on the chassis where the battery is grounded. It fixed mine right up. The autometer guages are very finicky when it comes to the ground.