97 Cutlass supreme only left brake light working.
. Hazards and Signals work fine,. Can't find the problem of right brake light not lighting up,
. I just replaced the turn signal switch in the column, works fine. Just got the car last week,

 

Have you changed the lamp?

 

Or at least check for voltage at the socket?

 

Yes,. Both new bulbs,. Getting power to all sockets but theleft side 'brake' light doesn't light up

 

If you are getting power to the left side socket, you need to look at the contact to the bulb or it may be a lack of ground issue.

 

power to the yellow and brown wires, yellow are running "dim" lights, the brown is for brighter turn, hazard or brake.
Starting to think problem might be in the harness connection from turn signal switch,.
. Bulbs and sockets are good,.
I'm stumped. Hope it's not the multiconnection switch,. Pretty sure the brake light current goes to the multi switch before running back to the bulb, so the switch controls the intermittent Turn/Brake light

 

Based on your subsequent post, I think you should explain what you mean by the above statement.

 

Left and right tail lights are both working when turn signals or hazards are applied, when I press the brake only right side lights up, left side just running lightt remains on,. Therefore All "bulb sockets" are getting power,.
there. Explained lol. Now I can't explain why when brakes are applied only right brakelight goes on, not the left,. Feel like I'm repeating myself.

 

Brown = "dim"/tail lights,
Yellow and green = turn signal and brakes.
The bulb brightness is determined by the filament size inside the bulb not the voltage supplied to the bulb.Swap the bulbs to prove that they work, don't rely on new = good when diagnosing. "Known good" makes the best test component.

Good luck!!!
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The tail light and the turn signal/hazard/brake lights are two different circuits and bulb filaments and are unrelated. You need to see where you are losing power for the brake light. The brown wire is for tail lights comes from the headlight switch. The yellow is for the turn/hazard/brake lights, it comes from the turn signal switch.

 

Ok thanks,. So the bulb isn't the problem?
. The yellow wire is not getting voltage from the switch I'll back track the yellow wire to the turn signal switch (the donut part with 18 pin connector) I just replaced 4 days ago,,or would it be the 3 way switch connected to the arm. (wiper/cruise/hight beam).
.

 

If the hazards and turn signals are working, the issue is in the turn signal switch. The brake light power is a single wire feed to the switch from the brake pedal and depending on the position of the turn signal switch it is directed to either side or if the turn signal switch is centered, then both sides.

 

That narrows it down, excellent,.
. The donut👍