The Ford Barn

koates · 01-03-2014, 01:54 AM

Hi there, If you read the specifications of those two types of ceramic resistors supplied by various auto houses you will note they are suitable for very specific current draw ranges. One from 2 to 4 amps draw and the other 4 to 6amps draw. Ceramic resistors cannot REGULATE the voltage, they only lower it depending on the current draw of the load being fed. Your gauges require a voltage REDUCED from 12 volts to 6 volts and the voltage to be REGULATED at 6 volts regardless of other loads turned on and off (lights,wipers,heater fan etc) in your vehicle. The requirement for a 6 volt regulated supply is to achieve consistent accuracy readings on your gauges regardless of outside voltage variations. I would not use a runtz on my gauges. Use a single reducer/regulator to supply all three gauges. Macs have one ,part # V12871, same one is also supplied by Dennis Carpenter. OR you can google "Voltage Reducers 12 to 6 volts" on ebay. You need about a 2 to 3 amps capable unit. There are many on here from as low as $3.00 each. That is the best and only way to go. Ceramic resistors are only good for heater fans, w/wiper motors, horns, valve radios etc where a specific current draw of the item can be established..and that way the resistance value in ohms of the resistor can be worked out. Hope this helps you. Regards, Kevin.

01-03-2014, 01:54 AM	#21
koates Senior Member Join Date: May 2010 Location: Melbourne Australia. Posts: 2,079	Re: Why won't the 12v to 6v ceramic reducers work for gauges? Hi there, If you read the specifications of those two types of ceramic resistors supplied by various auto houses you will note they are suitable for very specific current draw ranges. One from 2 to 4 amps draw and the other 4 to 6amps draw. Ceramic resistors cannot REGULATE the voltage, they only lower it depending on the current draw of the load being fed. Your gauges require a voltage REDUCED from 12 volts to 6 volts and the voltage to be REGULATED at 6 volts regardless of other loads turned on and off (lights,wipers,heater fan etc) in your vehicle. The requirement for a 6 volt regulated supply is to achieve consistent accuracy readings on your gauges regardless of outside voltage variations. I would not use a runtz on my gauges. Use a single reducer/regulator to supply all three gauges. Macs have one ,part # V12871, same one is also supplied by Dennis Carpenter. OR you can google "Voltage Reducers 12 to 6 volts" on ebay. You need about a 2 to 3 amps capable unit. There are many on here from as low as $3.00 each. That is the best and only way to go. Ceramic resistors are only good for heater fans, w/wiper motors, horns, valve radios etc where a specific current draw of the item can be established..and that way the resistance value in ohms of the resistor can be worked out. Hope this helps you. Regards, Kevin.