1972 Vega GT with a/c - fan blower stays on high setting

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1972 Vega GT with a/c - fan blower stays on high setting

Postby corvairdog » Fri Sep 19, 2014 7:58 am

1972 Vega GT. I can't get the blower to turn off and it won't change the fan speed setting. It seems to be blowing on high. The rest of the a/c controls work fine. It will turn on the a/c, heat, defrost, vent just fine. Is there anyway to fix it so fan can be turned off and the fan speed can be adjusted?
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby ROB » Fri Sep 19, 2014 8:16 am

Sounds like you have either a bad blower motor resistor, or a previous owner messed up things.
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby bugdewde » Fri Sep 19, 2014 10:22 am

Rob hit the nail on the head, more than likey. The power wire to the fan has 12 volts running to it... maximum. That powers the HIGH setting. In order to lower the fan speeds, the power goes through a resistor on the fan housing to get a lower voltage to power the fan for each lower speed setting. This resistor goes bad over time, leaving a full 12 volts to the fan at all times.
The resistor is usually on the fan housing for A/C cars.... under the dash for non-A/C cars.

It's possible, the resistor failed and the previous owner straight wired the fan so it only gets the full 12 volts.

Spenser seems to be a wiring guru... he's chimed in on this issue a time or two.
Here's one thread where he describes it's location and operation. viewtopic.php?f=1&t=40721

I typed in "fan motor location" in the search bar in the upper right corner of the screen.
It can use google to search posts on this site (really helpful, since if you only use the hbody site search function, you can only search a different topic every few minutes... something to do with spam attacks or something).... I was looking for a picture to assist.
But it's basically right on the fan housing under the hood.
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby corvairdog » Fri Sep 19, 2014 1:07 pm

Thanks for the reply. I'm not sure where to locate the fan housing on my a/c car to replace the resister. I thought there would be a picture but I didn't find one. If anyone has an a/c car and can help that would be greatly appreciated.

Also where can I get this part? I searched around and no luck so far. thanks.
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby Smiley » Fri Sep 19, 2014 6:27 pm

looks like this, the coils will be inside the AC housing under the hood.


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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby Monza Harry » Fri Sep 19, 2014 8:35 pm

CD The fan is supposed to run all the time it was once tooted as a safety feature, to make sure the inside of the car is in Positive Pressure to ensure that no unwanted fumes can migrate in. so even on the lowest setting the fan will run. If the fan is running at full speed in any position on the switch other than high (all the way up) then the switch is bad or it has been "Bypassed" (like mentioned above by all, wired direct). The Non A/C cars has the resistor right next to the blower motor on the engine side towards the right side unibody "Frame Horn" (inner Fender) I will try and take a pic' of the A/C set-up this weekend and post it up as soon as I can. ( I have had lots of that era car with out A/C, and only this one with) Harry
Last edited by Monza Harry on Wed Oct 01, 2014 9:10 pm, edited 4 times in total.
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby corvairdog » Sat Sep 20, 2014 4:09 am

Thanks everyone for responding. I appreciate a photo showing where I can find the faulty part. Also I searched everywhere and cannot find this part. Is there any other cars other than the Vega that use this same part?
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby stage169 » Sat Sep 20, 2014 9:50 am

View "B"Item 17.
Attachments
Vega blwr resistor.png
Vega blwr resistor.png (139.38 KiB) Viewed 438 times
Vega blower resistor.png
Vega blower resistor.png (37.49 KiB) Viewed 438 times
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby corvairdog » Sat Sep 20, 2014 10:15 am

Wow! Thanks very much. What's that search page you are using to find the results? :th:

EDIT - I think I found it - https://www.partsvoice.com/partsearch

WOO HOO! Thanks to everyone this forum is AWESOME!! :dance:
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby stage169 » Sat Sep 20, 2014 12:04 pm

SSSSSSSSSSSSHHHHHHHHHHHHHHHH it's a SECRET!!! :D

GM parts wiki http://www.gmpartswiki.com/query is a good place to search for the original GM part number.

It has been my experience to ask for a description of the part. Some places will even take pictures for you. Hopefully they won't think it is gold and give you a good price.

Brian
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby corvairdog » Sat Sep 20, 2014 2:55 pm

Thanks. That wiki is great. I'm getting a price of $100 with shipping for the this part :( Haven't heard back from all the vendors yet.
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby stage169 » Sat Sep 20, 2014 10:47 pm

That is crazy. Depending on what you want to do there is a chance you could fix yours. Looks like there are several with the same looking spiral wire that are a lot cheaper. Summit has a Dorman one for $11.00 http://www.summitracing.com/parts/rnb-9 ... aQodDpEAfA

Image
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby corvairdog » Sun Sep 21, 2014 6:59 am

Chicago Auto Parts sold me a NOS one for $45 with shipping. http://chgoautopts.com/. I'll update the post once I install. Thanks to everyone for responding. :th:
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby corvairdog » Thu Sep 25, 2014 8:31 am

Update - I put in the new blower resister and no change. In fact if I unplug the blower resister the fan still stays on high. Does that mean the previous owner hard wired the fan? I can't see anything unusual except for a green wire that is running off the left side of the a/c compressor running up to this harness. I'm not sure where to look for the hard wire running 12v straight to the fan motor. Attached are two pictures showing the wiring. Thanks to everyone for any help they can provide. :bang:
Attachments
SAM_0628.jpg
Wiring around blower
SAM_0628.jpg (227.92 KiB) Viewed 390 times
SAM_0629.jpg
green wire coming from a/c compressor
SAM_0629.jpg (187 KiB) Viewed 390 times
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Re: 1972 Vega GT with a/c - fan blower stays on high setting

Postby corvairdog » Fri Sep 26, 2014 7:29 am

Someone checked and said fan is not being wired direct with 12v. They say blower motor selector switch in car is at fault. My car has a/c can I replace just the switch that controls the fan speed behind the dash?
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