The flasher dissected

Did this some time ago. The old and the new turn signal flashers.
The new electronics uses parts available at your nearest Radio Shack store, a very simple oscillator with a transistor doing the switching. It blows very quickly if overloaded.
The old design was more complicated and uses a 50 amp silicon controlled rectifier for the switching. All components mil spec, btw. It can sustain a shorted load until the circuit breaker trips.
Hint: If you are looking for a good flasher, go for the old ones made in the 1960's.

So what NSN flasher unit do we want?

They all have the same NSN, so you got me there. The image below shows just three of many designs. The top one works and may be of older design.
The middle one is dated 1997 and doesn't work. The bottom one is a common new one like the one I took apart with low cost components. It doesn't work. I have several of them, all not working.
Be your own judge, but I would stay away from the flashers that look like the one on the bottom.
You can always add a relay to help prevent a blown flasher. Let the flasher turn on the relay and let the relay do the switching. That will also give you a slightly higher voltage to the lights. A mil spec 25 amp relay is perfect for this.

Justed replaced the middle one with the bottom one got it form Saturn. I will be looking for the top one. When I got the new one I thought it was going to better, just by the size of it.

Hi there
I have been researching many threads regarding signal lights and flashers. Bjorn you have impressed me with your knowledge of the flasher unit. Let me throw this one out for your take. Please forgive the heavy amount of content. All three M923 turn signals operate fine except the Rear passenger (right turn # 22 wire lead ) lamp is not illuminating at all. Below are the diagnostic results. ANY input is welcome and appreciated.
Signal assembly replaced with newer spotless signal unit from m105a1 trailer
All lamps tested in another socket and work fine. Even tested lamp on a 12 v car battery and got 1/2 bright illuminance.
100% lamps are in operational condition and light except the problem socket.
All lead wire number bands match up.
Wireharness at pintle looks fine, ie no pinches freys or metal to metal contact.


Ground connections on the following cleaned by light sanding:
Steering column to turn switch prongs
Steering column ground wire to firewall attached to flasher mount bolt.
Flasher unit to fire wall bolts.
Ground wires connecting flasher unit it fire wall bolts.
Rear right turn signal assembly bolts to frame.


Socket spring, soldier joint, wire lead and inside walls of socket pass visual inspection, and continuity test.


Continuity has been checked and confirmed on new signal assembly between truck frame, signal mount bolts, sockets, metal barrier plates, all braided ground wires. As far as I can tell continuity between same points across the new signal,appears to match that of all other three working signal assemblies. Voltage has been checked at all working turn signal sockets registered 22.5 max V DC. Here is the strange part... When voltage checked at said rear right turn signal lamp socket it is at 22.5 max v DC. Also no cetain if it is the same #22 wire from signal assemblies, but #22 wire at turn signal connector gave me 12 volts when disconnected with headlight switch on. Also I am under the impression that the flasher unit will flash all four or none at all, am I mistaken? Should I just replace it an see?
HELP, OVER!

Do you know anything about a "loud" flasher unit (that might be used in a Deuce)?

i.e., a flasher with a loud "click" (like those on UPS trucks) that makes it hard to overlook and forget that you have it on?

Just curious: any leads on that kind of item?

Another Ahab said:

Do you know anything about a "loud" flasher unit (that might be used in a Deuce)?

i.e., a flasher with a loud "click" (like those on UPS trucks) that makes it hard to overlook and forget that you have it on?

Just curious: any leads on that kind of item?

Click to expand...

Some folks have hooked up the turn signal circuit(s) to the low-air pressure buzzer:

http://www.steelsoldiers.com/showthread.php?5683-Bjorn-s-Low-air-signal-buzzer

http://www.steelsoldiers.com/showth...warning-buzzer&p=342103&viewfull=1#post342103

clinto said:

Some folks have hooked up the turn signal circuit(s) to the low-air pressure buzzer:

http://www.steelsoldiers.com/showthread.php?5683-Bjorn-s-Low-air-signal-buzzer

http://www.steelsoldiers.com/showth...warning-buzzer&p=342103&viewfull=1#post342103

Click to expand...

THAT'S the ticket. I'm good-to-go. Thanks a million!

Another Ahab said:

THAT'S the ticket. I'm good-to-go. Thanks a million!

Click to expand...

It's shocking how much good info is buried in the back archives of the site.

C

clinto said:

It's shocking how much good info is buried in the back archives of the site.

C

Click to expand...

Yeah it'd be a treat, wouldn't it, to have ALL the thread data collected, collated, and catalogued (for quick and painless reference).

And it would spare each new member having to re-invent the wheel, and slog through the countless threads to find that one nugget of gold (though I admit I like the search because of the unexpected unrelated gold you can stumble across, but it is random AND time consuming).

But the issue is kind of like what Light Houses were to Ship Owners/Captains/Sailors back in the day: everybody wants them, sure, but no single ship-owner's in charge to get them all built.

Maybe like maddawg suggested (in pooling resources to cast a few parts for some m4 Shermans), if every (+/-) subscriber kicked in small change, maybe we could hire a Fifth Grader somewhere to do it (they know EVERYTHING)!

Nicledoux said:

.........Voltage has been checked at all working turn signal sockets registered 22.5 max V DC. Here is the strange part... When voltage checked at said rear right turn signal lamp socket it is at 22.5 max v DC. Also no cetain if it is the same #22 wire from signal assemblies, but #22 wire at turn signal connector gave me 12 volts when disconnected with headlight switch on. Also I am under the impression that the flasher unit will flash all four or none at all, am I mistaken? Should I just replace it an see?
HELP, OVER!

Click to expand...

According to this, #460 is the same as #22. I would suspect that the turn signal switch is the problem. Remember that a high impedance DVM will measure and indicate voltages that may be close to zero on a wire when loaded down with a light bulb. Use a light bulb to check the presence of a voltage.

Well thanks for the input there Bjorn. Bought a new turn signal switch figuring that was the issue after testing the connector pins. Seemed to have an intermittent internal contact issue. I Installed the new TS switch and...bupkis, Nada...wondering if the stop switch was involved somehow I went to work vexing on what the issue was. I had a chat with a coworker with classic trick repair experience, they were stumped as well. Now I am a professional illumination engineer and I am taking this really personally, as to why I can't get this dagone bulb to light. 4 + hrs of switching left with right turn signal leads and verifying it was providing enough voltage. finally after exhausting my options I slightly crimp the bulb socket so that I had to really use pressure to set the build and blink, blink, blink! It was working. Tested the old turn signal DOLT it worked. Live and learn. Thanks all.

Happens to the best of us.