Joe: The switch and its wiring should look like the first picture below. (The white wire is hidden behind the yellow.) If so, you can verify proper wiring using a paper clip.

Disconnect all 6 wires noting which one plugs in where.

Use a paper clip to connect the FEMALE terminal that the WHITE wire plugs into to the FEMALE terminal that the PINK terminal plugs into.
Press the brake pedal.
The left rear turn/brake lamp SHOULD light. If not, fix the wiring before continuing.
Remove the paper clip.

Use a paper clip to connect the FEMALE terminal that the WHITE wire plugs into to the FEMALE terminal that the VIOLET terminal plugs into.
Press the brake pedal.
The right rear turn/brake lamp SHOULD light. If not, fix the wiring before continuing.
Remove the paper clip.

Use a paper clip to connect the FEMALE terminal that the WHITE wire plugs into to the FEMALE terminal that the LIGHT BLUE terminal plugs into.
Press the brake pedal.
The left front turn lamp SHOULD light. If not, fix the wiring before continuing.
Remove the paper clip.

Use a paper clip to connect the FEMALE terminal that the WHITE wire plugs into to the FEMALE terminal that the DARK BLUE terminal plugs into.
Press the brake pedal.
The right front turn lamp SHOULD light. If not, fix the wiring before continuing.
Remove the paper clip.

Use a paper clip to connect the FEMALE terminal that the YELLOW wire plugs into to the FEMALE terminal that the DARK BLUE terminal plugs into.
Turn on the ignition switch.
The right front turn lamp SHOULD light. It may flash or just come on solid, depending on your flasher. If not, fix the wiring before continuing.
Remove the paper clip.

Once all above are as "SHOULD" the wiring out to the lights is correct. Fix any that are not as the SHOULD be before continuing.

Now let's check the switch before installing it.

Turn off the key.
Plug all 6 wires of the switch into the harness with the switch just laying on the floorboard.
Slide the switch into the middle position.
Press the brake pedal.
Brake lights on rear both sides SHOULD light.

Turn on the key.
Slide the switch to the counter clockwise position.
One side (I think the passenger's side, but I don't have a switch to look at right now) SHOULD be flashing BOTH front and rear.
Slide the switch to the clockwise position.
The other side SHOULD be flashing BOTH front and rear.
Attachments
Clipboard01.jpg (23.35 KB, 81 downloads)

Last edited by Bill Hanlon; 03/31/2025 11:21 PM.

'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.