Not sure which Wiki you're talking about, but https://en.wikipedia.org/wiki/VGA_connector is clear:

Pin 9 KEY/PWR formerly key, now +5V DC, powers EDID EEPROM chip on some monitors

It's a key pin, i.e. one intentionally left empty to ensure correct orientation of connector.

In very late VGA systems it was co-opted for +5VDC for EDID, to allow the monitor to talk back to the card with its capabilities, but with old stuff that's not going to work and you encounter VGA connectors with the key intentionally blocked - so that's why you don't want the pin in the cable either (unless you support EDID).

Since this is on topic, I have a situation that I do not want a VGA monitor to communicate its specs because it operates at much higher resolutions than detected just fine.

Do I only need to remove pin 9 to disable the sense pin and resolution detection or are there other id pins I need to pull?

When monitor is powered, lack of pin 9 won't make a difference. SCL and SDA are where the EDID info is communicated, if either is missing the driver cannot interrogate the monitor anymore but how the driver will behave is uncertain in such a case. For example Catalyst 6.2 will max out at 1600x1200 in such a case and while it shows higher resolutions, they are those stupid virtual resolution panned in 1600x1200 physical image things...

On my monitor I created a new EDID which has all the higher resolutions listed in it and the driver will then give me those without the stupid panning stuff.

Tiido wrote on 2024-06-17, 08:20:

When monitor is powered, lack of pin 9 won't make a difference. SCL and SDA are where the EDID info is communicated, if either is missing the driver cannot interrogate the monitor anymore but how the driver will behave is uncertain in such a case. For example Catalyst 6.2 will max out at 1600x1200 in such a case and while it shows higher resolutions, they are those stupid virtual resolution panned in 1600x1200 physical image things...

On my monitor I created a new EDID which has all the higher resolutions listed in it and the driver will then give me those without the stupid panning stuff.

1600x1200 is better than what I have going on, sadly all my VGA cables are molded so I’m not sure how to easily get rid of the pin(s) ?

Based on your description I need to remove pin 9,14 and 15 then?

Definitely not 14, it is Vsync. Only 12 (SDA) and/or 15 (SCL). There's no need to remove both (unless you want to be polite), just one is enough to break EDID communications.

As far as removal goes, fine nozed pliers will help, but you can use fine tweezers or a screwdriver to wiggle/bend the pin until it breaks off while not disturbing the other ones. This can take a while depending on when metal fatigue sets in.

Other option is to go inside the monitor and disconnect one of the wires from a socket, this is reversible too but a lot more work. Similarly you can saw a trace on the video card side and perhaps prevent the problem with any other monitor too.

The missing pin dates back to the PS/2 at introduction in 1987 when PS/2 VGA monitors was introduced as well.

Cheers,