Rear window interchange years

[69hurstolds]

So I went to the Dealer ordering book for 1985, and found that the RPO TS6, High-mounted stop light, was listed as OPTIONAL equipment for 98 Regency, Calais, and Ciera LS and Ciera Brougham. Funny too, it shows a drawing of grid lines across the face of the brake light lens.

Which means Cutlass Supreme body styles would need to buy the high-stop mounted brake light accessory kit and have it dealer-installed if you wanted it. GM p/n 999375. Listed for less than 20 bucks back then. You can still find them on ebay here and there. Thing is, the universal kit is a tad different from year over year. The kit I had looked exactly like the factory unit but molded in black and had a factory style shield/rubber boot thing on it, but it was a tad longer with a steeper angle which would need to be cut to fit a G47 body style.

 

[565bbchevy]

In my 83' Monte I installed a 3rd brake light many years ago but my windows are tinted so I am guessing the tint helps with any issues having the rubber boot touching the glass.

 

[fleming442]

I thought all Supremes had the 3rd brake light?

 

[565bbchevy]

I thought all Supremes had the 3rd brake light?

My Regal didn't get one until 86' my 85' didn't have one.

 

[69hurstolds]

1986 was the mandatory factory-installed 3rd brake light for all G-body cars in the U.S. All cars sold in the U.S., really. Before then, it wasn't available except as an accessory option. They knew it was coming way back in 84, though. They also had a different 3rd brake light accessory for amber-turn signal lamp cars (assuming export?) apparently too. I don't know the difference, but it's part number is 999376. Still looks the same to me. Maybe it's the wiring.

But the instructions do say to butt that shield/rubber boot up to the window to make contact to reduce glare/light bleed. So maybe that's why they didn't want it rubbing up against the window grid on the straight element windows? I dunno.

Personally, I think it's a bunch of bullcrap on a G-body because it always appeared as an afterthought and just looked tacky. JMO. If they were going to do it, they could have used a small unit at the top of the rear window. Maybe they tried that and failed, because where it is doesn't really affect visibility anyway, but then again, in the mid-80s, LED's weren't used on cars. Now, just about everything is LED. Even headlights. Would have made it much easier to relocate a 3rd eye brakelight. I wonder if there's a square-inch requirement for the lamp itself? The skinny ones seem long, and the fat ones seem to be pretty short and square-ish.

 

[fleming442]

My Regal didn't get one until 86' my 85' didn't have one.

I was being facetious.

 

[pontiacgp]

I thought all Supremes had the 3rd brake light?

not these ones, they used hand signals...

 

[Olgambler84]

There's no legal issues with it at all. Windows will physically fit, but the grid line will have a "hole" in it if you use an 86-up rear heated glass without the 3rd brake light installed. And if you use a 3rd brake light on the 85-below heated glass, try and not let the rubber lip touch the grid lines if possible. The grid still will work, but the rub is (pun intended) the rubber lip on the lamp is really there to block peripheral light from the 3rd brake light from diffusing on the glass and reflecting back into the cabin so it works best when it's actually touching the glass to block any reflection. But with that, the rubber lip could rub up against the grid lines and eventually cause a service issue. Hence they changed the grid line routing for 86 and up as to not be in the way of the mandatory third brake light so it sort of wraps around the brake light. Up through 1985, the grid lines for heated glass go straight across. In 1985, the third brake light was actually an dealer-installed option for GM so that should allay any fears of any legal requirements. Now the legality for the manufacturers may have had something to do with it, but not if you installed it. Same pieces/parts as the later factory versions. They were trying to make a buck off customers with the then-new regulations coming into play for the 86 model year. I used to have one of those 3rd brake light accessory kits in the box. The instructions said something like the rubber gasket may need to be trimmed to fit the back window. I never seen me ever using it so I sold it many moons ago.

Up through 1985 grid lines:

Here's a page out of the 1985 Cutlass brochure on the options and accessories pages...right in the middle...

I couldn't find a pic of an 86-up glass itself with the gridlines, but if you look closely at this pic of my 87 442, you can see how the bottom 3 gridlines drop down when it gets to the area around the 3rd brake lamp;

View attachment 132023

Nice, thank you for the info. The donor I have is a 85 and it does have a lot of extras. I’ll definitely try and snatch up as much as I can from it. If it wasn’t so rusty id keep it