Old cars used to use an thermal device to make the turn indicators flash - a heater, a bimetallic strip, etc. The one in my MG makes me laugh, it's slightly erratic so it goes flash...flash....flash..flash...flash.
They were replaced with solid state flashers, although I suspect mechanical relays with some simple logic were in the middle.
What was the last vehicle sold in the US that came with a thermal flasher? Was it before or after the carburetor went away? Carbs died in the US in 1990 or 1991, with the exception of (apparently) the 1994 Isuzu pickup.
I have found a listing for a thermal flasher on Autozone that includes my 1966 Cadillac. And is also listed as compatible with a 1995 Jeep Wrangler as well as a 1997 Mazda B4000. So that may answer my question.
https://www.autozone.com/electrical-and-lighting/turn-signal-hazard-warning-flasher/p/novita-turn-signal-hazard-warning-flasher-ll552/849393_0_0
I replaced one in something newer, possibly my 99 Cavalier. They stayed around a long time.
In reply to Wally (Forum Supporter) :
A thermal flasher, or a relay with logic in it? Looks like that thermal one from Autozone fits a 1995 Cavalier.
Amazing lifetime, no matter what. Simple and cheap and reliable enough.
Keith Tanner said:
In reply to Wally (Forum Supporter) :
A thermal flasher, or a relay with logic in it? Looks like that thermal one from Autozone fits a 1995 Cavalier.
Amazing lifetime, no matter what. Simple and cheap and reliable enough.
Not only that, they also generally made the "blinker" noise all by themselves!
The one in my '66 Cadillac goes "boing boing" instead of "click click", I'm going to replace it just because of that.
Mazda used a "CPU" in their late carbureted cars.... it handled the turn signal flashing, amongst a couple other things. This is the flasher assembly for my '81 RX-7, that I pulled apart to resolder the pins after kicking the CPU failed to make the turn signals work anymore.
It is a relay controlled by circuitry. A flasher relies on the current going through it to set the flash speed, this guy will flash the same speed no matter how many bulbs are burned out!
(This IS the same company, that, 35-odd years later, did the "ticks of fuel" method for the fuel gauge, I assume so the needle doesn't swing high or low when cornering)
In reply to Pete. (l33t FS) :
GM does ticks of fuel as well, although I don't know if it's used for the gauge function or just instantaneous consumption. We had to get the translation of that right to get the gauge working on the V8 ND. I did indeed run it dry a time or two before we figured it out...
It should flash faster when a bulb is out, by design. But four ways are a consistent speed. The NA Miata had something similar - you can make it flash at normal speed with LEDs by changing out one resistor. And yes, you occasionally have to pull one apart to reflow a solder joint or two.
I can say for certain that the FB RX-7 unit does not care if you have missing or burned out bulbs. I have a few missing housings on the '81.
Pretty sure my 2003 Tacoma was thermal. When I went LED I had to change it out to get the proper click cadence.
I'm quite familiar with these, never knew how they worked.
In reply to preach :
A lot of electronic flashers will do that too, to alert the driver that there's a blown bulb. Even a Tesla will if there's a broken wire to an LED, so it's obviously a programmed behavior.
Ford used a mechanical flasher in my 96 F350, which was fuel injected.
Keith Tanner said:
In reply to preach :
A lot of electronic flashers will do that too, to alert the driver that there's a blown bulb. Even a Tesla will if there's a broken wire to an LED, so it's obviously a programmed behavior.
Mercedes will flash the outside lights at the normal speed, but flash the dashboard indicator (and turn signal sound) fast to alert the driver.
And then they will substitute a fog light or brake light for the bulb it thinks is out, which confuses people who don't know what bulb is supposed to light up.
In reply to Pete. (l33t FS) :
That's pretty funny and clever.
In reply to Keith Tanner :
Not so much when a doofus inspects the car and says all the bulbs are working, then two days later when it comes back and is assigned to a non doofus, non doofus sees the "bulb out" message on the display, looks in the service info to see which bulb is what, notes that the turn signals are lighting up the rear fog lights per designed in failure management, and the service manager has to have an awkward conversation.
My 2000 Firebird has a "mechanical" flasher. I'm sure that was the same thru 2002.
When the Camaro Z28 was being designed for 2015, they wanted to delete the radio for weight savings but the turn signal sound is put through it and out the speakers.
I hate the way the 'electronic' flashers sound.
the most annoying flasher in the world is in my Disco. It's not that it doesn't work, they work very well. Yes, "they" Land Rover, in their infinite wisdom, had two seperate flashers for the turn signals. One for the right and one for the left.
And they wonder why their vehicles have a reputation for being cantankerous.
