Motor vehicle directional signals have been around almost as long as cars, and as early as 1909, a device was patented that had hand-shaped lights that indicated to other drivers which way a vehicle intended to travel. Obviously, that one didn’t catch on. Neither did the mechanical signaling device invented by silent-film star Florence Lawrence in 1914, which, after a button was pushed by the driver, a sign would pop up from the rear bumper indicating which way the car was turning. The first modern directional signal was patented in 1925 by Edgar A. Walz, Jr., although no one was interested in it either, at least until after his patent expired 14 years later. That’s when, in 1939, the U.S. automaker Buick first introduced the “Flash–Way Directional Signal,” which operated in the familiar way – a stick, mounted on the steering column. In its original incarnation, this turn signal only flashed the rear lights; by the next year, front lights were flashing as well. By the end of WWII, directional signals were standard in most American automobiles.

While there are several different designs out there for turn signal switches, they classically used some form of a thermal switch (in this case called a thermal flasher). The core of this switch includes a resistor that heats up when current flows through it. This is attached to a bimetallic spring- essentially an arched strip made up of two sandwiched metals with very different thermal properties, one that expands quite a bit as it warms and the other that doesn’t. The result is that when current is flowing (when you turn on the blinker), the resistor heats up the arched bimetallic spring which in turn is connecting the two terminals, allowing the lights to come on. As it heats up, one of the metals begins to try to straighten itself out as it expands, but initially can’t because the other metal is holding it in its arched form.  Eventually, the heat builds enough where the metal trying to straighten itself out wins the battle and the bimetallic spring straightens, disconnecting the two terminals.

At this point, no electricity is flowing and the lights are off.  Because no power is flowing, the resistor and the bimetallic spring rapidly cool to the point where the other metal pressing to reform itself into the arched shape wins, and there is another snap as it once again bends back into shape and re-connects the terminals, starting the process over again. So in these thermal flashers, the clicking noise you hear is just this bimetallic spring snapping back and forth from its arched form to a straightened form and back again. One tell-tale sign that you have a thermal flasher in your car is that when a light goes out, the flash rate of your blinkers will slow down- less electricity = more time needed for sufficient heat to build to snap the spring.  In the extreme, where too little current is flowing (like if you try to swap out your incandescent bulbs for LEDs), your blinker will simply not blink, staying on.  On the other end of the spectrum, if you hook up a trailer or something with more lights, it will speed up the blinking rate and in the extreme perhaps even damage your thermal flasher.

Another common device used to create the blink in your blinkers is an electronic flasher.  oxford ms motorcycle repairInstead of using heat and a bimetallic spring, this device simply uses some electronic circuit to control a relay.  motorcycle boots adjustable calfInside a mechanical relay, applied electricity to an electromagnet creates a magnetic field that switches a metallic armature, which in turn makes an audible clicking noise.  harley davidson welding helmetsWhen the electricity is no longer applied to the electromagnet in the relay, a spring moves the armature back the other way, either connecting the circuit or disconnecting depending on the type of relay (whether it’s designed to be switched on or off by default).motorcycle helmet wellington nz

This type of system has the advantage of not inherently changing the blink rate based on the electrical draw of the lights.  motorcycle dealers in barnsleySo switching to LED lights or hooking up trailer lights won’t necessarily affect anything, though this does vary somewhat depending on the design of the circuit, particularly in how the system is designed to detect and respond to a burnt out light bulb. motorcycle helmet backpack amazonBut, in general, as long as you’re not drawing more power than the wires, fuse, etc. can handle, the system should blink at a constant rate, with the relay clicking away as it switches the lights on and off.red wing boots albuquerque There is also another type of electronic flasher that is a solid state flasher, meaning it has no moving parts (making it incredibly long lasting and reliable), perhaps using a solid state relay. 

This type of system does not inherently click unless the designer specifically chose to add something to do so, possibly added as an extra indicator to the driver that the blinker is on. In most cases, though, there will be no click with a solid state flasher. If you liked this article, you might also enjoy subscribing to our new Daily Knowledge YouTube channel, as well as: How Turn Signals Work Turn Signal Usage Rate (SAE) Turn, Turn, Turn: A History of the Turn Signal What causes the clicking sound when I turn on the blinkers? Where is the turn signal noise generated in your car?View MirrorsRear View MirrorMotorcycle BlackMotorcycle Parts99 LedSignal LightsParts Led35 99Led TurnForward24950 motorcycle-parts LED Turn Signal Lights Indicators Rear View Mirrors For Motorcycle Black New BUY IT NOW ONLY $35.99 LED Turn Signal Lights Indicators Rear View Mirrors For Motorcycle Black New...Visibility is a good thing, especially at night. It took a while, but the Run-N-Lites folks eventually

came up with a kit for the R1200GS that replaces the bulbs with a grid of LEDs, two rows of which remain on all the time (lower photo above). I believe these yellow marker lights help motorists identify the approaching object as a motorcycle, as opposed to a car with one headlight out. also draw less power than bulbs, and last practically forever. power part is a good thing, but the computer that monitors the lighting system won't see enough power draw from the turn signals after the conversion, so load resistors must be wired in parallel with the turn signal LEDs. More on this later. The kit came to me in a plastic sandwich bag with a sheet of poorly written instructions and most of the parts I'd need. seem to be have recycled from the rear Lite Buddies because they make frequent references to the tail light. The instructions also reference an illustration and wiring schematic that are not included. a few Lite Buddies installations now, so these omissions didn't slow

me down too much. I was a little unclear about how to wire the resistors, but was able to puzzle out the solution with several re-readings of the The crimp on connectors provided (the red things in the photo above) are hateful devices that will ruin the wiring harness if used, so these went in the spare parts drawer for a very rainy day. Posilock T-connectors that I got from Aerostich, which not only make a secure connection but also provide strain relief for the wire beingThe crimp on connectors just slice the insulation (often clipping some wires in the process) and leave the tapped wire free to vibrateI also found a pair of load resistors I mentioned earlier, along with the LED arrays and a short piece of heat shrink tube. The running light needs a source of twelve volt power that is on while the bike is running, and the instruction sheet suggests using the hot lead to the parking lamp in the headlight. That seemed reasonable enough,

but to make access easier I ended up removing the front upper fenderThis also meant removing both tank side covers. sound like a big deal, but it only took ten minutes and really saved a lot of thrashing later. I tackled the turn signal housings next. The lenses are held in by a single screw on the rear, and backing it out allows the outer edge of the lens to pivot forward so that the catch at the end of the prong on the other end of the lens can disengage the bottom of a mating slot in the housing (red arrow in the photo below). I'd broken a prong before during the Lite Buddy install on the K1200RS, so I worked carefully to avoid repeating that this time. With the reflector visible, I used a screwdriver to tip it out of the housing and reveal the wires on the back. The wires came off by using some needle nose pliers to tug on the spade connectors, freeing the reflector for installation of the LED grids on started by cleaning the reflector surface with come electrical contact

cleaner and a soft, clean terry cloth towel. This removed any dirt and mold release that might have present, promoting adhesion of the double faced tape on the back of the LED grid. Then I fed all three wires through the hole in the back of the reflector. The holes were big enough that I didn't have to enlarge them. With the wires fed almost all the way through, I removed the backing from the tape and carefully positioned the array into the reflector, paying attention so that the LEDs ended up parallel with the open end of the reflector and the array was centered I didn't like the looks of the wires rubbing on the prong that formerly contacted the bulb, so I used some of the shrink wrap to provide someThen I bent the yellow wires back around the housing so that one ran on each side. The black shrink wrap covers load limiting resistors that keep the LEDs from burning out, so there's no room for trimming wires or otherwise trying to make things fit easier.

The two blue wires splice to a long black wire that draws power from the parking lamp, and that I had to route out of the housing and down the turn signal stalk. No provision was made in the kit for a connector for this wire, so the first time I need to remove the turn signals for maintenance I'll probably install one in the already crowded turn signal housing instead of cutting and re-splicing the wire. I poked around on the back underside of the headlight assembly until I found the parking lamp. It's a bit hard to get to (small hands help) but it's only held in by the friction of its rubber housing. the temptation of pulling on the lead and instead was able to get (just barely) a grip on the housing and wiggle it free. stripped back the outer insulation for about three inches so I'd have access to the power lead (that's the cloth looking stuff in the photo I had enough free lead to work with I tried to slip the cap end of the

Posilock T-connector in place and screwed the bayonet in to pierce theThat's when I found out that the wire was smaller than was really intended to work well with these particular Posilocks, because the slot in the cap let the bayonet push the wire to the side instead of piercingI wrapped a little bit of electrical tape around the wire (the white/blue one, since brown is always ground on a BMW motorcycle) to beef up the wire and the Posilock worked fine. I repeated the LED grid install on the other turn signal, connected the spade connectors to the grids and the long black wires to the parking light wire and fired up the bike to run a smoke check. I got the four rows of running lights just fine, but when I hit the turn signal switch I got a very fast flash rate and a fault light on the information display. That meant I'd have to install the load resistors to trick the computer into thinking that I was still running light bulbs.

With the fender off it was easy to find a spot for the resistors just behind the oil cooler on the left side. I just used a couple of zip ties to bind them to the fairing bracket, then crimped on an eyelet to ground to the bracket (I picked up a bolt used to hold my HID driving light ballasts in place). The other end of each resistor got hot tapped into the hot lead going to each turn signal LED grid using another pair of Posilock T-connectors. That meant tracing the turn signal wires back through the stalks and stripping off the cloth insulation far enough back inside the bike so that the T-connector wouldn't prevent the turn signal wires from reaching back up into the turn signalThe left side is pretty easy to get to, but space was starting to get tight with two Posilocks already installed. I elected to run the other load resistor wire across the bike to the right turn signal and tap into the hot lead there. Since there wasn't any connector on the

wire, I managed to fish it through existing zip ties so it was held nice and tight during the traversal. With the resistors back in place the fault lights went out and the flashing rate returned to normal. I started to re-install the turn signal lenses in the housing and discovered that with all the extra wire it's a very tight fit. The yellow wires needed to be as close to the old bulb base on the back of the reflector as possible, and the blue leads ended up at the wide end of the reflector. I took my time getting things right so that the reflector was sitting solid in the housing before I attempted to install the lens. It went in prong first with the outer, pointy end of the lens pivoted forward. When the prong end hit bottom I rotated the pointy end into the housing and installed the securingI repeated the process on the other side, then ran one more smoke check to be sure nothing was shorting or had become disconnected.