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Discussion Starter #1
I am hoping someone can help me out. I recently put a tach and gauge cluster in my 70 SS with a new wiring harness. I sold the idiot cluster to my buddy, with my original harness. He went to install it, and said there was no plug for the heater fan in the harness. Did any years (70-72?) come with no heater wiring in the harness? I read somewhere that 72 cars go out throught he firewall, is this true? If so, did I have a 72 harness in my car originally and now pass it on to him? He said he is just going to take the wiring from his original dash and put it in. Any help would be appreciated.......Tom
 

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Well, I'll give this a shot and maybe your will find an answer in here. If the engine harness came out of an A/C car, chances are the heater blower connector was cut off. That's because the non A/C heater blower wire was not used. It received power from an option harness.
The 72 engine harness is different than the 70/71. In 72 the main 12 volt line, to the fuse block, comes off the starter to a horn relay on the firewall. In 70/71 the main 12 volts came up the forward lamp harness from the horn relay by the radiator.
 

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The plug you are referring to: Are you talking about the plug for the blower motor or the plug for the fan switch? Did you have A/C on the dash you gave to your buddy? As John said, the dash harness is seperate from the "option harness". The option harness goes thru the firewall on my '71 and connects the blower motor, fan resistors, relay, etc.
 

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Discussion Starter #4
OK, here goes. It is a 70 car with Air. So this is why there are no wires for the fan switch or the blower motor in the harness? I guess the harness I got was for a car without air, because there are plug ins for the heater controls. Did both 70 and 71 cars with air have the option harness through the firewall? Is it possible I have a 71 car that someone turned into a 70? :confused:
 

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Sorry, I am no expert on 70 v.s 71. I think they are very similar though and it sounds like you are on the right track IMO. My nephew has a 70 w/AC and I am pretty sure he also has the option harness through the firewall. It does sound like you have a dash harness from a non AC car. As far as what year car you have, I am sure you can confirm that by the VIN.
 

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Discussion Starter #6
Yes, the vin shows it to be a 70 car, and so does the cowl tag. But I know when I bought it the dash had the white numerals, and the head light switch was for a 71-72. I was wondering if someone could have pulled the vin and cowl tag off a wrecked 70 SS, and installed them on a 71 body, then changed the nose and rear bumper. I don't know, just sometimes things don't make sense. It has all 70 interior though. I have the original build sheet that matches the vin and cowl tag also.
 

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Doesn’t make sense. The dash harness should have the same heater connections for either a non-A/C or an A/C car. The dash harness would be the same. On the A/C car, the heater control connector doesn’t directly plug into the control switch. Plugs into an option harness which in turn plugs into the A/C-heater control. If you go to one of the harness suppliers such as M & H, you will not find “An A/C dash harness”.
www.wiringharness.com
 

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Discussion Starter #8
It is weird, but from the looks of it, the harness that was in my car, that I sold to my buddy appeared to be in original shape. (not molested) He started untaping it, thinking someone had cut the wire. He could find no evidence that it was ever there. The orange wire that is supposed to connect in the fuse block was completely missing also. It's weird, I'm stumped. He cut the heater wires off his old harness, and added them to this one. He started it up, and everything works ok, so I feel better about it.
 
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