Random thoughts - blinkers

[cj847]

I am confused on why/how my blinkers suddenly quit working. They worked one day 100% then the next day nothing. I checked all the fuses and "easy" stuff and found no smoking gun.
Let me know if you have some ideas.

Now for my random musings. I decided to review the entire circuit, which meant I had to understand where the electrons are going. This is what I think happens or is supposed to happen:

-12V key on power goes thru the flasher and into the purple wire which goes to the switch. I confirmed this at the column connector with a multimeter and a light bulb.
-Thru meshing of contacts the power goes to the various wires to the blinker filaments (yellow, green, lt blue, dk blue).
-My problem is the purple wire has power but when you move the switch nothing happens. (no continuity to any of the blink light wires.)
-Then I went and got an old blinker switch from another truck that had failed. I tore it apart to see where the magic happens. The assembly is such that there is really nothing to go wrong. It is just brass on brass contact. The nubs could wear out over time but I'm doubting that could happen overnight.



Now that I've studied this stuff I've confused myself and I have some questions for any experts out there.
I understand the purple wire powering the blinkers before you hit the brake. But when you hit the brake 12v+ comes in via the white wire from the brake switch. This is 12V that has not been thru the flasher. Does this only power the light on the non-blinking side?


PS> Here are some pics for anyone who wants to geek out with me.

[Rust_never_sleeps]

You can search up and download a Service Manual for your year from this site, including the wiring diagram

[Steeveedee]

here-
https://67-72chevytrucks.com/vboard/...ghlight=hatzie

[raggedjim]

Originally Posted by cj847

I understand the purple wire powering the blinkers before you hit the brake. But when you hit the brake 12v+ comes in via the white wire from the brake switch. This is 12V that has not been thru the flasher. Does this only power the light on the non-blinking side?

Short answer is yes. The white is hot when the brakes are pushed. The turn signal will determine which brake light is on or if both are on when not in use (this is in normal emergency flashers off condition).

This is a poor drawing but shows the state of the brake lights in each of the 3 positions. The gray lines show when the 12v isn't being sent to a light.

[raggedjim]

The second part of the circuit is the purple powered circuit.

This shows what circuits are powered by the purple in each of the 3 positions. The brake light that was disconnected from the white 12v will be powered up by the blinking purple ( as well as the front turn signals).

[raggedjim]

That brown wire is for hazard lights.

[cj847]

Well, it turns out my switch was bad. I just found it weird to suddenly break without any other problems preceding. My guess is the purple wire somehow lost continuity.

Problem solved.

PS> Be sure to check your new in box turn signal switch for proper operation before install. Ask me how I know....lol.