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Old 01-08-2023, 04:55 PM
Mlburton83 Mlburton83 is offline
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Default 1970 Formula Firebird Rear Defog Switch

Hey...hopeful someone can help. I have a numbers matching 1970 Formula 4 speed in excellent condition. It has a factory rear defog that I'm attempting to get back in working condition. The dash switch is bad and I've purchased a replacement that was suppose to work for a 1970, however, the wiring harness doesn't fit. I want to see if anyone has a suggestion on where I might be able to find original or replacement that would work? Thanks in advance for any help.

  #2  
Old 01-08-2023, 07:01 PM
Ramairnacho Ramairnacho is offline
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Default Rear defogg

I am learning I too have rear defogg. Do you have ac too? If it doesn't work the little resistors needs to be replaced. It's the skinny red tube. Use an ohms meter to check it for flowing of electrons. Original one can be fixed or find a nos one like I did,
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  #3  
Old 01-08-2023, 07:10 PM
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Formulabruce Formulabruce is offline
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The switch you probably bought is for an electric grid rear window de icer used from 71 through 81.
Originals for 1970 are tough to find. Show us a pic of your switch..front and back close ups.
I have used a 1981 turbo light switch for this and bought the correct decal our host Ames sells now.

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Old 01-08-2023, 07:44 PM
Ramairnacho Ramairnacho is offline
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Default Defogg switch

I bought this one in a little package deal and it looks like they replaced the resistor with moder ones. Im.not an expert and do hit and miss sometimes. Also my 70 said defogg on left only.
I haven't check it yet but I think they had same issue with fuse like little red resistor that controls flow of electrons or basically hi and low speed. If this works then your original can be fixed just need to get correct resistors like this one. I'm not a group expert but buy what I might need in future. Im.not selling my dad's car it's part of my family and as time progresses parts will get harder to find.
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  #5  
Old 01-09-2023, 02:33 AM
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Formulabruce Formulabruce is offline
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Quote:
Originally Posted by Ramairnacho View Post
I bought this one in a little package deal and it looks like they replaced the resistor with moder ones. Im.not an expert and do hit and miss sometimes. Also my 70 said defogg on left only.
I haven't check it yet but I think they had same issue with fuse like little red resistor that controls flow of electrons or basically hi and low speed. If this works then your original can be fixed just need to get correct resistors like this one. I'm not a group expert but buy what I might need in future. Im.not selling my dad's car it's part of my family and as time progresses parts will get harder to find.
That resistor was added to adjust the fan speed on low probably. We did it at the dealer due to noise complaints and this is a major reason why they went with a grid. Oddly enough, the V2 and bigger cars kept a smaller self contained air defogger.

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