The Ford Barn

aussie merc · 01-23-2024, 06:38 AM

the fan switch resistor has failed in my 39 does anyone know what size/value the it was so i can repair the switch Thanks

Bob/Pa · 01-23-2024, 07:39 AM

resistors are usally color coded with stripes and that tells the value.

Terry,OH · 01-23-2024, 08:24 AM

Are you asking for the ohm resistance and wattage of the small resistor mounted to the rear of the heater blower switch?

Jack E/NJ · 01-23-2024, 09:23 AM

Google search 'flathead ballast resistor 6 volt' for vendors who ship to your location. $10-20usd.

aussie merc · 01-24-2024, 06:31 AM

terry yes ignition ballasts i got boxs of em but the little suckers on the fan switch their a bit of a mystery

Jack E/NJ · 01-24-2024, 07:00 AM

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Sorry, missed the word 'fan'. How many amps does the fan motor draw at 6volts?

aussie merc · 01-24-2024, 07:16 AM

unsure about current draw

Terry,OH · 01-24-2024, 07:20 AM

I believe the resistor is used to put the fan motor on slow speed, If it is open circuit the slow speed will not work, the motor will stop.

Jack E/NJ · 01-24-2024, 09:56 AM

Terry >>I believe the resistor is used to put the fan motor on slow speed, If it is open circuit the slow speed will not work, the motor will stop.>>>

Yes, my understanding too. If you bypass the busted resistor with a wire, the fan should run at full speed.

6v fans typically draw ~8 amps or ~50watts at full tilt.

To cut the power in half you'd need a ~1 ohm resistor with a ~25 watt heat dissipation rating. Like an ignition resistor, they can get quite hot.

Juergen · 01-24-2024, 11:11 AM

My Ford heater switch measures between 1-1.5 ohms. Even though it is NOS, the switch is put together by compressing the connections which makes the actual resistance fluctuate by the contact resistance. If Jack's current consumption is cut in half during slow speed operation, then the wattage is 4 times 4 times (1-1.5) or about 16 t0 25 watts so the conclusions are consistent. If your resultant speed is not what you like, modify the resistance a little around these values.

01-23-2024, 06:38 AM	#1
aussie merc Senior Member Join Date: Sep 2016 Location: sydney australia Posts: 1,034	what size resistor ???? the fan switch resistor has failed in my 39 does anyone know what size/value the it was so i can repair the switch Thanks

01-23-2024, 07:39 AM	#2
Bob/Pa Senior Member Join Date: May 2010 Location: Oakmont, Pa (Longwood) Posts: 297	Re: what size resistor ???? resistors are usally color coded with stripes and that tells the value.

01-23-2024, 08:24 AM	#3
Terry,OH Senior Member Join Date: May 2010 Posts: 4,751	Re: what size resistor ???? Are you asking for the ohm resistance and wattage of the small resistor mounted to the rear of the heater blower switch?

01-23-2024, 09:23 AM	#4
Jack E/NJ Senior Member Join Date: May 2010 Posts: 2,173	Re: what size resistor ???? Google search 'flathead ballast resistor 6 volt' for vendors who ship to your location. $10-20usd.

01-24-2024, 06:31 AM	#5
aussie merc Senior Member Join Date: Sep 2016 Location: sydney australia Posts: 1,034	Re: what size resistor ???? terry yes ignition ballasts i got boxs of em but the little suckers on the fan switch their a bit of a mystery

01-24-2024, 07:00 AM	#6
Jack E/NJ Senior Member Join Date: May 2010 Posts: 2,173	Re: what size resistor ???? Sponsored Links (Register now to hide all advertisements) Sorry, missed the word 'fan'. How many amps does the fan motor draw at 6volts?

01-24-2024, 07:16 AM	#7
aussie merc Senior Member Join Date: Sep 2016 Location: sydney australia Posts: 1,034	Re: what size resistor ???? unsure about current draw

01-24-2024, 07:20 AM	#8
Terry,OH Senior Member Join Date: May 2010 Posts: 4,751	Re: what size resistor ???? I believe the resistor is used to put the fan motor on slow speed, If it is open circuit the slow speed will not work, the motor will stop.

01-24-2024, 09:56 AM	#9
Jack E/NJ Senior Member Join Date: May 2010 Posts: 2,173	Re: what size resistor ???? Terry >>I believe the resistor is used to put the fan motor on slow speed, If it is open circuit the slow speed will not work, the motor will stop.>>> Yes, my understanding too. If you bypass the busted resistor with a wire, the fan should run at full speed. 6v fans typically draw ~8 amps or ~50watts at full tilt. To cut the power in half you'd need a ~1 ohm resistor with a ~25 watt heat dissipation rating. Like an ignition resistor, they can get quite hot.

01-24-2024, 11:11 AM	#10
Juergen Senior Member Join Date: May 2010 Posts: 503	Re: what size resistor ???? My Ford heater switch measures between 1-1.5 ohms. Even though it is NOS, the switch is put together by compressing the connections which makes the actual resistance fluctuate by the contact resistance. If Jack's current consumption is cut in half during slow speed operation, then the wattage is 4 times 4 times (1-1.5) or about 16 t0 25 watts so the conclusions are consistent. If your resultant speed is not what you like, modify the resistance a little around these values.