# Turn signal flashing rate - Why doesn't mine match others?
**URL:** https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582
**Category:** Factual Questions
**Created:** [December 10, 2008, 6:01pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582 "2008-12-10T18:01:26Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Dryfreeze](https://boards.straightdope.com/u/Dryfreeze)
#### Post date: [December 10, 2008, 6:01pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/1 "2008-12-10T18:01:26Z")
It has been a very long time since I have started a thread here at the SMDB, but I feel compelled to express this burning question inside of me.
Every time I pull into the left turn lane at a light or something similar and there is a car ahead of me with the left turn signal on, I stare at the signal and attempt to compare its flashing with that of the signal on my car. Occasionally, I find a vehicle that the rate of flashing is similar to that of my vehicle (2003 explorer sport trac), but never does it exactly match.
I have even wound up behind a similar explorer or sport trac with no avail.
Why? Why must my turn signal flash in such a random manner as to never line up with someone else’s? Ahhhhhhhhh . . . . I beg you, SMDB, answer this question for me and ease my signal frustrations!
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### Author:  [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)
#### Post date: [December 10, 2008, 6:26pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/2 "2008-12-10T18:26:46Z")
The flashing is controlled by a thermal switch. When the light’s off, power is sent through a resistive wire, creating heat. The heat makes a piece of spring straighten and closes a contact that routes power to the bulb. When power is going to the bulb, the resistive wire cools down, the spring bends, and the contact is broken, power goes back to the wire and the cycle starts again.
The timing is dependent on minute differences in the design and manufacture of the switch. They _could_ put time and effort into tuning the switch so that they are all the same, but there’s no reason to, as long as it goes on and off in a broad range of acceptable times, then it’s good to go.
I suppose some modern cars may go for the electronically timed approach, those should all be the same.
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### Author:  [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)
#### Post date: [December 10, 2008, 9:22pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/3 "2008-12-10T21:22:37Z")
Making it even tougher to match up, the blink rate is also affected by the overall resistance of the turn signal bulbs and their wiring. This is intentional - when a bulb burns out, the flash rate changes from tick - a - tick - a - tick - a to tikka-tikka-tikka-tikka to alert you to the burned-out bulb.
So, you have multiple variables - the inherent timing of the flasher device itself, the resistance of the bulbs, and the resistance of the wiring and sockets - all affecting the blink rate and all making it so that any two random cars will most likely not blink at the same rate.
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [December 10, 2008, 9:39pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/4 "2008-12-10T21:39:56Z")
I came here for an argument.
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### Author:  [@tomndebb](https://boards.straightdope.com/u/tomndebb)
#### Post date: [December 10, 2008, 10:13pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/5 "2008-12-10T22:13:47Z")
> [@beowulff](#):
>
> I came here for an argument.
Too bad.
This question has a factual answer, (probably already supplied), and the thread is being moved to **General Questions**.
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### Author:  [@sailor](https://boards.straightdope.com/u/sailor)
#### Post date: [December 10, 2008, 10:16pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/6 "2008-12-10T22:16:23Z")
> [@Cheesesteak](#):
>
> I suppose some modern cars may go for the electronically timed approach, those should all be the same.
Not really. If you use an RC circuit the tolerance of the values of the components will make them differ quite a bit.
> [@beowulff](#):
>
> I came here for an argument.
The five minute or the full half hour?
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### Author:  [@Musicat](https://boards.straightdope.com/u/Musicat)
#### Post date: [December 10, 2008, 10:18pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/7 "2008-12-10T22:18:56Z")
Also note that a burned out bulb, which changes the circuit characteristics, may result in a different blink rate (at least in the years/models I am familiar with). Just because it blinks on your dash doesn’t mean it is working at both front and back of your car.
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### Author:  [@Joey\_P](https://boards.straightdope.com/u/Joey_P)
#### Post date: [December 10, 2008, 10:19pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/8 "2008-12-10T22:19:41Z")
> [@beowulff](#):
>
> I came here for an argument.
I’m sorry, this is abuse.
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [December 10, 2008, 10:34pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/9 "2008-12-10T22:34:28Z")
> [@Joey\_P](#):
>
> I’m sorry, this is abuse.
I want to complain!
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### Author:  [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)
#### Post date: [December 11, 2008, 2:09am UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/10 "2008-12-11T02:09:07Z")
I was behind a car waiting in a left turn lane a couple weeks ago, and our blinkers were in sync the whole time. It was probably over a minute, with no noticeable changing of the relative phase of blinkers, until we made our turns and the blinkers went off. It was amazing. I’ve never had that happen before.
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### Author:  [@MEBuckner](https://boards.straightdope.com/u/MEBuckner)
#### Post date: [December 11, 2008, 2:58am UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/11 "2008-12-11T02:58:25Z")
Clearly you should have followed that car to wherever it was going. That other driver was your _soul mate_, man!
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### Author:  [@Rick](https://boards.straightdope.com/u/Rick)
#### Post date: [December 11, 2008, 5:49am UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/12 "2008-12-11T05:49:12Z")
> [@Cheesesteak](#):
>
> The flashing is controlled by a thermal switch. When the light’s off, power is sent through a resistive wire, creating heat. The heat makes a piece of spring straighten and closes a contact that routes power to the bulb. When power is going to the bulb, the resistive wire cools down, the spring bends, and the contact is broken, power goes back to the wire and the cycle starts again.
You have that backward. When no current is flowing the system is cool, when the light is turned on a bimetalic strip heats up from the flow of current, bends and breaks the circuit. This stops the flow the current and when the bimetalic strip cools, it makes contact again, and the light comes back on. Lather, rinse repeat.
> [@](#):
>
> I suppose some modern cars may go for the electronically timed approach, those should all be the same.
I would almost bet money on a 2003 being an electronic circuit. The familiar click you hear is computer generated.
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### Author:  [@postcards](https://boards.straightdope.com/u/postcards)
#### Post date: [December 11, 2008, 6:14am UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/13 "2008-12-11T06:14:39Z")
> [@Dryfreeze](#):
>
> …there is a car ahead of me with the left turn signal on…
People use signals where you live?
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### Author:  [@Sapo](https://boards.straightdope.com/u/Sapo)
#### Post date: [December 11, 2008, 9:32am UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/14 "2008-12-11T09:32:02Z")
> [@Rick](#):
>
> I would almost bet money on a 2003 being an electronic circuit. The familiar click you hear is computer generated.
Am I being whooshed? (or was that sound computer generated?)
Are you really saying that that annoying tick tick is not an unsolvable problem of engineering but done on purpose just to annoy me? That I am paying money for it? Is there a way to disable it in my Jeep Liberty 2004?
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### Author:  [@Shamozzle](https://boards.straightdope.com/u/Shamozzle)
#### Post date: [December 11, 2008, 10:04am UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/15 "2008-12-11T10:04:10Z")
> [@Sapo](#):
>
> Am I being whooshed? (or was that sound computer generated?)
>
> Are you really saying that that annoying tick tick is not an unsolvable problem of engineering but done on purpose just to annoy me? That I am paying money for it? Is there a way to disable it in my Jeep Liberty 2004?
I would say you want that click.
I used to drive a commercial truck that was sans click and did not have an auto-cancel mechanism. Plus, the turn signal dash indicators were precisely blocked by the body of the steering wheel.
Drive 40 km with the left turn signal on and then ask me if you don’t feel like a douche.
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### Author:  [@Rick](https://boards.straightdope.com/u/Rick)
#### Post date: [December 11, 2008, 1:45pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/16 "2008-12-11T13:45:17Z")
> [@Sapo](#):
>
> Am I being whooshed? (or was that sound computer generated?)
>
> Are you really saying that that annoying tick tick is not an unsolvable problem of engineering but done on purpose just to annoy me? That I am paying money for it? Is there a way to disable it in my Jeep Liberty 2004?
No whoosh, true fact. Try this experiment. Go turn on the key, and then turn on your 4 way flashers. Then leaving the flashers on, turn the key off.
Do you still get the click, click noise with the key off? If so they are probably a mechanical can. If the lights still flash, but no click click they are electronic.
No way to disable that I know of.
As **Shamozzle** says that is a click you want to hear.
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### Author:  [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)
#### Post date: [December 11, 2008, 2:13pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/17 "2008-12-11T14:13:19Z")
I don’t want to hear it. If I leave my blinker on too long, I eventually get a dinging to let me know.
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [December 11, 2008, 2:19pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/18 "2008-12-11T14:19:44Z")
> [@ZenBeam](#):
>
> I don’t want to hear it. If I leave my blinker on too long, I eventually get a dinging to let me know.
You can use [this](http://www.cksinfo.com/clipart/construction/tools/pliers/diagonal-cutter-pliers.png) tool to turn off the clicker.
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### Author:  [@Philster](https://boards.straightdope.com/u/Philster)
#### Post date: [December 11, 2008, 3:19pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/19 "2008-12-11T15:19:02Z")
Electronic devices that mimic mechanical sounds are in use around us everyday. Digital cameras, cell phones, cash registers, etc.
Many of these electronic devices aren’t opening lens shutters, or having keys hit sensors, or ringing bells.
Even the trackball on some phones have very faint ‘rolling sounds’ that are electronically generated.
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### Author:  [@Colophon](https://boards.straightdope.com/u/Colophon)
#### Post date: [December 11, 2008, 3:27pm UTC](https://boards.straightdope.com/t/turn-signal-flashing-rate-why-doesnt-mine-match-others/476582/20 "2008-12-11T15:27:58Z")
> [@beowulff](#):
>
> You can use [this](http://www.cksinfo.com/clipart/construction/tools/pliers/diagonal-cutter-pliers.png) tool to turn off the clicker.
Wouldn’t that be breaking the [law](http://en.wikipedia.org/wiki/Automotive_lighting#Turn_signals)?
> [@](#):
>
> Worldwide regulations stipulate an audiovisual telltale when the turn signals are activated; this usually takes the form of one combined or separate left and right green indicator lights on the vehicle’s instrument cluster, and a cyclical “tick-tock” noise generated electromechanically or electronically.
Besides, I don’t know why anyone would want to turn off the ticking noise - without it it would be very easy to drive with your indicators on without realising.
Edit: the electronic “shutter” noise on camera phones, though, I would gladly kill. Why does it have to be so LOUD?
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