What most people don't know is that a 6 volt Zener Diode is all that is needed on the gauges. One for each. Cost is about .89 cents (or less). Face the Silver Stripe away from the gauge and you are good to go. Do not do this for anything but the gauges.

That is what this is:
http://www.ebay.com/itm/Dash-Gauge-Voltage-Reducer-12-6-Volt-Runtz-Diode-to-resistor-b-/291161623894?hash=item43ca95cd56:g:wM4AAOSwfcVUEzHN&vxp=mtr


Deve

1950 Chevy 3100 Deluxe Cab
1950 Chevy 3100 Standard Cab
In the Stovebolt Gallery
The Think Tank
More info and tips at Deve's Technet