johnbu Posted August 9, 2003 Share Posted August 9, 2003 According to my 72 chevell/monte carlo service manual, the heater resistor is located on the top of the heater box. A three wire harness plugs into the resitor connector. Is this correct? My heater resistor harness is not connected and I cannot find the correct location of the resistor. Can anyone explain the function of the resistor? Any help is appreciated. Link to comment Share on other sites More sharing options...
alex's72fgmc Posted August 9, 2003 Share Posted August 9, 2003 according to my assembly manual for the 72 It is behind the dash on top of the heater box "if you take the dash off you should see it fairly easy above the glove box an directly behind it. Are you asking about the three wire in the engine compartment or the interior??? just want to make sure i got you question answered correctly. alex Link to comment Share on other sites More sharing options...
wallaby Posted August 10, 2003 Share Posted August 10, 2003 That heater resistor is mounted to the heater box ductwork and is mostly flush on the outside except for the terminals that accept the 3-wire harness. The bulk of the resistor is on the inside of the heater box. The resistor gets hot, so they placed it inside the ductwork where air circulation will cool it when the heater blower is running. The resistor is the gizmo that provides different voltage outputs so you can have several fan speeds for the blower. The high-speed blower is a different circuit, and does not use the resistor. Link to comment Share on other sites More sharing options...
Landshark Posted August 11, 2003 Share Posted August 11, 2003 FYI, the resistor for the air conditioned systems is under the hood, on the evaporator case, on the left front. It has 4 wires. Link to comment Share on other sites More sharing options...
johnbu Posted August 16, 2003 Author Share Posted August 16, 2003 Thanks for the posts...although my three wire harness under the dash is not connected, I still have multiple fan speeds. I have removed the glove box and all duct work and still cannot find the three prongs. On my 71 Chevelle, It was really obvious. Thanks again, I'll take another look. Quote: <font face="Verdana, Arial" size="2">Originally posted by Landshark: FYI, the resistor for the air conditioned systems is under the hood, on the evaporator case, on the left front. It has 4 wires.</font> Link to comment Share on other sites More sharing options...
johnbu Posted August 18, 2003 Author Share Posted August 18, 2003 I definately do not have the resistor on the heater box. So now the question is where does the three prong wiring plug connect to under the dash. The colors of the harness are light blue, yellow and orange. The plug on the end is white. Two of the prongs run vertical, and the top prong runs horizontally. Cannot find any other option but for the connection to the resitor on all of my wiring diagrams. Any help is appreciated. Quote: <font face="Verdana, Arial" size="2">Originally posted by Landshark: FYI, the resistor for the air conditioned systems is under the hood, on the evaporator case, on the left front. It has 4 wires.</font> Link to comment Share on other sites More sharing options...
Guest Posted November 11, 2003 Share Posted November 11, 2003 Quote: <font face="Verdana, Arial" size="2">Originally posted by johnbu:I definately do not have the resistor on the heater box. So now the question is where does the three prong wiring plug connect to under the dash. The colors of the harness are light blue, yellow and orange. The plug on the end is white. Two of the prongs run vertical, and the top prong runs horizontally. Cannot find any other option but for the connection to the resitor on all of my wiring diagrams. Any help is appreciated.</font> Link to comment Share on other sites More sharing options...
Guest Posted November 11, 2003 Share Posted November 11, 2003 Quote: <font face="Verdana, Arial" size="2">Originally posted by metz 6565: </font> I just put a heater core in my 70 MC I also need to know where that 3 wire white plug goes ,thanks for the help! Link to comment Share on other sites More sharing options...
Landshark Posted November 12, 2003 Share Posted November 12, 2003 If you have air conditionning, your build sheet will have a option called AC conversion. Some cars are wilred for AC in the factory loom. The AC conversion cars have the wiring in the loom for non-AC heater fan, (the 3 wire connector you mention), and a seperate harness that goes from the AC control to the evaporator case, and the fuse box. This does all the heater/AC control. The 3 wire connector goes nowhere. Ignore it. ------------------ 70 Monte, 454, auto. 70 Monte, 454+.030, 4speed.71 Monte, 350 beater. 71 Monte SS 454. 65 Corvette coupe 365hp. Link to comment Share on other sites More sharing options...
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