Heater Resistor what does it do ??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

woodrow59 · 02-16-2007, 09:35 PM

Heater Resistor, Does it only control the fan speed ?????

Got my heater control rebuild kit from Paul today. Decided to take everything out and clean and paint. Took off the heat resistor and it fell apart. Am I ok putting everything back together and then putting in a new resistor.

I plugged in an old fan switch and it worked fine (blew on high, but I don't know if that switch is good)

**oldgold70c10** · 02-16-2007, 09:47 PM

Yes, the hearter resistor just controls fan speed. I assume you have a non-AC truck.
In high, the fan motor runs directly off the 12v from the battery, but to make the motor run more slowly in meduim and low, it is put in series with a resistor. Your fan will still work without the reistor, but only in high.

woodrow59 · 02-16-2007, 10:06 PM

thanks oldgold70c10 I understood that completly,,,,,,were you a teacher ???????

**oldgold70c10** · 02-16-2007, 11:04 PM

Quote:

Originally Posted by woodrow59

thanks oldgold70c10 I understood that completly,,,,,,were you a teacher ???????

No, but very glad to help

GMC Jim · 02-17-2007, 12:14 AM

Point of interest....The blower specs were: Standard Heater :- 2650/2950 RPM - 10 amp. Air Conditioning :- 3700 Min. RPM - 16.5 amp.

If you have replaced the standard blower with the high output blower ,a relay should be used as this is standard with vehicles with factory installed air conditioning. The blower switch will eventually fail ( sooner rather than later) if a high output ( 16.5 amp ) blower is used without a relay.

02-16-2007, 09:35 PM	#1
woodrow59 OzarkHillbilly in Atlanta Join Date: May 2002 Location: Douglasville, Ga. Salem, Mo. Posts: 386	Heater Resistor what does it do ??? Heater Resistor, Does it only control the fan speed ????? Got my heater control rebuild kit from Paul today. Decided to take everything out and clean and paint. Took off the heat resistor and it fell apart. Am I ok putting everything back together and then putting in a new resistor. I plugged in an old fan switch and it worked fine (blew on high, but I don't know if that switch is good) __________________ 72 custom/10 LWB 68 Longhorn C20 Custom Camper (sold)

02-16-2007, 09:47 PM	#2
oldgold70c10 Who's got steelies? Join Date: Feb 2006 Location: Morrison, Oklahoma Posts: 1,026	Re: Heater Resistor what does it do ??? Yes, the hearter resistor just controls fan speed. I assume you have a non-AC truck. In high, the fan motor runs directly off the 12v from the battery, but to make the motor run more slowly in meduim and low, it is put in series with a resistor. Your fan will still work without the reistor, but only in high. __________________ 1969 C10 LWB W/ 250 I6 & 3spd 1970 C10 with '67 small window cab, 68 front end, blue; 305/TH350, 3.08 limited slip rear end, manual brakes, power steering; & 4-wheel drums-My daily driver. 1975 Chevelle Malibu Classic Coupe 350/th350 mint green 1970 C20 Suburban 350/700R4 4.10 gearing green & white 1978 Big 10 Silverado 350/th350, working ac, 2 tone blue-My summer daily driver 1983 GMC 1500 Sierra 305/SM465 2.73 rear end How to add a trip odometer to your 67-72 stock speedometer How to rebuild your Q-Jet My Truck Page My Youtube Channel

02-16-2007, 10:06 PM	#3
woodrow59 OzarkHillbilly in Atlanta Join Date: May 2002 Location: Douglasville, Ga. Salem, Mo. Posts: 386	Re: Heater Resistor what does it do ??? thanks oldgold70c10 I understood that completly,,,,,,were you a teacher ??????? __________________ 72 custom/10 LWB 68 Longhorn C20 Custom Camper (sold)

02-17-2007, 12:14 AM	#5
GMC Jim Senior Member Join Date: Dec 2002 Location: Portland, Oregon Posts: 901	Re: Heater Resistor what does it do ??? Point of interest....The blower specs were: Standard Heater :- 2650/2950 RPM - 10 amp. Air Conditioning :- 3700 Min. RPM - 16.5 amp. If you have replaced the standard blower with the high output blower ,a relay should be used as this is standard with vehicles with factory installed air conditioning. The blower switch will eventually fail ( sooner rather than later) if a high output ( 16.5 amp ) blower is used without a relay. __________________ '71 GMC;fleetside;PB/PS/AC/CC/402 Eng./Custom Paint/110,000act miles/3 fuel tanks(52gal).



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