About a dozen years ago I spent lots of time asking this question all over the place and ended up with two replies with pictures showing this as the correct spot. This was my car after I mounted the switch. I hope this helps.

Straight up from the splined shaft on the door handle.

I have to cut my panels for the power lock switches as well as the power vent switches so I'm glad you got me to search for that picture!

notop wrote:

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Also looking for tinted side glass for 1966 Parisienne convertible.

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 All 6 pieces?

I'm pretty sure I can find you door glass but the 1/4 glass could be an issue.

I thought I would post the interchange here for you in case it helps at all. It's a bit of a strange bird for the door glass and a couple of exceptions on the 1/4 glass as well. It's not as simple as any full size Chev Olds Pontiac Buick or Cadillac.

Door glass

66 Le Sabre or Wildcat conv

66 Electra 2 dr

66 Cadillac conv

66 Starfire and 98 2 dr ht

66 Olds conv

66 Pontiac conv 

66 Grand Prix

 

1/4 glass

65-66 Le Sabre and Wildcat conv

65-66 Chev conv

65-66 Olds conv except 98

65-66 Pontiac conv

 

Starting in 65 the full sized GM's had curved glass I'm afraid, so no option to cut it. 

Yes, all the way up to and including 64 full size. Not so for our cars once the X frame ended though.