[LH Lead-Foot]

While the dual filament bulb was used for 50+ years, I think they now called 2057's. Either way, they list them by both. I have seen every type of bulb mistake or failure known to man, not to mention the "Blue Scotch-Lock" under the rear bumper when someone decided to add trailer lights. Can you say "Green Copper Wires"?

Start with basics. Use a combination of extension to reach the seat, but hold the brake pedal on. Check for voltage and bulb type. I always solder new ground onto the fixture and the socket to the body. You'l have to wire wheel that crimp, then find some non-electrical soldering flux / acid. Run new BLK wire to nearby bolt with "Star" washers, but include a connector for service.
Use WD40 as cleaner to wipe the harness wires to see the colors for ID.
If you have the glass fuses, the stop lamp fuse is over used with current. Check both side for voltage with test light. ATO/ATC fuses are great, but painless complete harnesses are so expensive. I guess this is one reason for my obsession with dielectric grease.
(Tip; If using tape on wires or harness covers, use a dab of black weather strip adhesive in the end...it will not unravel. Plus, if you need to remove tape on harness, go to fabric store and purchase a couple of "Seem Rippers". They have protective point that has sharp center hook. They work great & cheap.

I had to take a different job because left elbow / pinched ulnar nerve that made me cry while holding a 1/2" air impact just to remove the lugs nuts on a SUV, I found myself as service manager at a boat dealer with 8 techs. Mercury marine sold gigantic tubes of dielectric grease ($20) and service manuals insisted it was to be used on everything electrical.

Sorry to hear about your 4 legged friend as I have lost 4. I feel the pain.
My black lab was born in my hands (Farm Boy) but with one eye and no one wanted him. Didn't feel like having another, but kept him anyways. We became one machine, work habits, nap time, play-time, time of day and sleep. He would jump in bed by my feet, wait 15 minutes until I got settled, then place his head over my ankles/ feet for his pillow. He was over 7 years old within my enclosed fence 7 foot high and in March, the garden was bare, so I left the garden gate open with allowed him access to 28 ft of public sidewalk. He would bark at other sometimes, but people are weird when it comes to dogs. They must figure they would jump a 7' fence and kill them.
Someone threw something over that was soaked in antifreeze, he ate some of it & in 2 days his kidneys, liver and white blood cells where gone. Lady "Vet" told me the antifreeze would create this activity. Had to put him down that day, 30 days after my 60th B-day. Never been right since. Being home all day creates a different bond with certain breeds of dogs as each breed has their own characteristics, while this leads to a dog/human best friend. Was not ready for that to end. No more!

A guy working on a restoration can say, there is not a bolt or nut on this vehicle I have not touched. This makes it yours. Hoping to get leather samples today for the buckets, doors and console accents. I hope to start the mock-up because I am using the BCM from donor that allows me for RKE, lights, horn, power windows, content theft and a lot more to operate from mostly ground inputs via class 2 serial data. I have a TECH2 scan-tool from Hewlett-Packard, the original company. There are a lot of Chinese stuff on eBay they have copied since GM built a plant to tap the huge market in the East. The platform names change in some cases, but owning a Buick is a mark of success over there.

Hope you find time for your project, while I try to figure out how to stand & walk without pain. New RFA starting in two weeks. Yeah!