C3 Defogger or Defroster?

[Tom R.]

Early C3 buyers were offered a defroster RPO C50 but 1973-75 buildsheets refer to those as defoggers. Not sure how early buildsheets (Corvette Order Copy) listed those but curious.

In 1976 we see C49 Rear Window Defoggers offered which I'll assume were the beginning of the use of electronic metal strips (heat elements) to melt frost and/or ice.

I take it than the C50 was ductwork that just blew heated air onto the rear window...not unlike the front window defroster.

In 75, convertible buyers could buy C50, defogger. Anyone have this option or familiar with it?

[Terry M.]

Re: C3 Defogger or Defroster?

Tom,

I don't have one -- but we judged a number of them in 1970-72s back in the dark ages when I was 1970-72 NTL. I also had the honor of PVing cars with this feature. The C50 in either coupe or convertible just blew cabin air at some parts of the rear window. They have no heating element and the only warmed air it picked up was whatever was generally in the cabin. I had a similar system on a 1965 Impala back when, and it worked well for fog or haze on the interior of the window, but any snow build-up or dew on the exterior was affected very little unless the temperature in the cabin resembled the tropics. This might be less of an issue on the Corvette with a vertical rear window than my Impala with an acre of gently sloped rear glass.

[Robert R.]

Re: C3 Defogger or Defroster?

Hi Tom, Would agree with your assessment to defogger for air blowing onto the window, while defroster using the electric strips imbedded into the glass. I have the C50 option on my '73 convertible. The fan basically blows the interior cabin air. There is no heat element. And there are two speeds available, low where you barely hear the fan, and high where you really hear the fan. Have not been in a situation yet to need to use it, and I'm sure it would take a while as the foam seals between the two ducts just barely seem to touch much less offer a tight seal to deliver the air.

[Warren F.]

Re: C3 Defogger or Defroster?

Tom,
On my 1971 Corvette Order Copy, the C50 option is referred to as REAR WINDOW DEFROSTER

[Robert R.]

Re: C3 Defogger or Defroster?

Ok this is confusing. Just looked at my Vette Vues Fact Book for 73-77. There is an Order sheet for a 1973 that shows C50 as "Defogger, Rear Window (Forced Air). And then on page 170, a Window sticker from a 1977 that shows: "C49 Electric-Clear Rear Defogger".

[Brian G.]

Re: C3 Defogger or Defroster?

On our '75 coupe buildsheet C50 = Defogger

[Tom R.]

Re: C3 Defogger or Defroster?

Ok this is confusing. Just looked at my Vette Vues Fact Book for 73-77. There is an Order sheet for a 1973 that shows C50 as "Defogger, Rear Window (Forced Air). And then on page 170, a Window sticker from a 1977 that shows: "C49 Electric-Clear Rear Defogger".

Yes...my point!

I suspect that those assigned the duty of "better" describing new features were tasked with what to call this new technology of using electric elements to heat glass and therefore serve as a defroster, defogger and demelter. It looks like the describers, probably engineers, left C50 as heated forced-air and a defroster since that's what it had been called. And than transitioned to an electrical unit as the defogger. But than I guess they had to be consistent with heated forced air that was used to "defrost" the windshield.

I had a VW back in the 1960s and heat came from the block with a fan to blow it...it was a terrible defroster.

[Hugh P.]

Re: C3 Defogger or Defroster?

My build sheet says Rear Window Defroster, C50. I had judges asking me what the little knob near the gas pedal was It is the rarest option on my car, only 4257 built in 72, just a little rarer than my power steering delete. When you cannot roll your windows down it actually works pretty well tho noisy little devils.

[Warren F.]

Re: C3 Defogger or Defroster?

Hugh,
Rear Window Defroster shows only 2221 production in the 1972 model run. 1968 year is really scarce at 693 ordered.

[Hugh P.]

Re: C3 Defogger or Defroster?

Hugh,
Rear Window Defroster shows only 2221 production in the 1972 model run. 1968 year is really scarce at 693 ordered.

Somewhere I read 2211 roadsters, 2046 coupe, will have to check for my documentation, thanks H

[Tom R.]

Re: C3 Defogger or Defroster?

So...C50 was just a bunch of hot air! The phrase DEFOGGER appears on buildsheets for late model C3s whether air ducts or electric strips.

Thanks guys.