Need help with buzzer in LED automotive turn signal circuit

[Tim Burchfield]

Hi. Brand new here so excuse me if I don't follow protocol. I have LED turn signals in my old English sports car powered by an electronic flasher. The P terminal on the flasher is supposed to power the turn signal indicator. My car did not come with a turn signal indicator light so I want to add a buzzer to let me know when the turn signals are on. I installed the buzzer described below with the power from the p terminal on the flasher and the ground to the car body. The buzzer works great. But when the turn signal switch shuts off the blinker stops but the buzzer continues for a few seconds ending in a drawn out pitiful squeal. I'm guessing that there is some power still in the flasher when the turn signal switch is turned off. Can anyone suggest something to stop the buzzer form continuing after the power to the flasher is cut? The car is a 12 volt negative ground system.

Tim

 

[duke37]

There will be a reservoir capacitor which retains some voltage.
This could be reduced in value.
A bodge could be added to drop the buzzer voltage when the input power is removed.

 

[73's de Edd]

Try shunting the buzzer with a 100 ohm resistor to start with. Evaluate to see if that quenches the hang on noise . . . both adequately and quickly enough for you.
If so, then step on up gradually, to higher values 220 330 470 1k ohm values until you meet the point where you are using the highest value of resistance to please your desired result.

 

[AnalogKid]

If 73's idea does not work for you, then there are more options. Please give us more information about the electronic flasher device/circuit/dingus. Is it powered from the turn signal switch, or powered constantly and controlled by an input signal from the turn signal switch?

ak

 

[Tim Burchfield]

If 73's idea does not work for you, then there are more options. Please give us more information about the electronic flasher device/circuit/dingus. Is it powered from the turn signal switch, or powered constantly and controlled by an input signal from the turn signal switch?

ak

Analog, here's the flasher information:
EF33RL Turn Signal Flasher Relay, LED Compatible, 3 + Ground Wire Prongs, 12 Volts

• Type: Electronic
• Pilot Circuit: Yes
• Prongs: 3 + Ground Wire
• LED Compatible: Yes
• 25 amp

The flasher only receives power when the switch is activated.

 

[AnalogKid]

Here is the datasheet on the flasher.
http://cecindustries.com/pdfs/EF33RL.pdf

What happens if you connect the beeper to the main turn light output (L)?

ak

 

[Tim Burchfield]

Here is the datasheet on the flasher.
http://cecindustries.com/pdfs/EF33RL.pdf

What happens if you connect the beeper to the main turn light output (L)?

ak

The beeper is connect to the L terminal and it functions as designed when the turn signal switch is activated. But when the switch clicks off the beeper continues for about 10 to 15 seconds and gradually gets quieter and finally stops. Thanks for the data sheet.

 

[AnalogKid]

I installed the buzzer described below with the power from the p terminal on the flasher and the ground to the car body.]

???

 

[AnalogKid]

The beeper is connect to the L terminal and it functions as designed when the turn signal switch is activated.

I installed the buzzer described below with the power from the p terminal on the flasher and the ground to the car body.]

???

 

[Tim Burchfield]

???

Yeah, confusing. The flasher has there terminals X L and P and an external ground wire. The X terminal is wired to a 12 volt source (only on when ignition switch is on). The L terminal goes to Indicator Relay. The L terminal is meant for a dash turn signal indicator light. I have it wired to the positive side of the buzzer and the ground side of the buzzer goes to the chassis. My car did not come with a dash indicator light. I hope that clears it up. I've attached a wiring diagram if that helps. The direction indicator warning light is replaced by the buzzer.

 

[AnalogKid]

The L terminal is meant for a dash turn signal indicator light. I have it wired to the positive side of the buzzer and the ground side of the buzzer goes to the chassis.

Don't you mean the P terminal?

ak

 

[Tim Burchfield]

Silly to expect someone to help you when you can't keep your Ps and Ls straight. Sorry. Yes, you are correct, I meant the P terminal. The P terminal is connected to the buzzer.

 

[AnalogKid]

What happens if you connect the beeper to the main turn light output (L)?

ak

ak

 

[Tim Burchfield]

ak

I'll try it when I get home.

 

[73's de Edd]

Sir Tim Burchfield . . .

GREAT ! help . . . . . with the further info of the whole wiring diagram.

I'm seeing the pins 4 and 8 of the "Indicator Relay" as having two coils for dual relays inside and the coils sharing a common connection that goes to metal case ground and that gets grounded to the body frame.

Our contacts of interest on that relay would be the #1 initially, so connect to that with the piezo and have the piezos other connection going to ground. See if that accomplishes all of your needs and with no final acoustical decaying yowl.

If that doesn't work move on to connecting the Piezo to to #2 and try BOTH the right or left turn indicator positions to see if one of them is accomplishing the feat.

If so, it is then merely in need of a set of directional steering / isolation diodes from #1 and #2 of the relay to the Piezo with the Piezos other lead grounded, so that it will then work for bioth right and left turn functions..



73's de Edd

 

[AnalogKid]

If so, it is then merely in need of a set of directional steering / isolation diodes from #1 and #2 of the relay to the Piezo with the Piezos other lead grounded, so that
it will then work for bioth right and left turn functions.

First, wouldn't it be Indicator Relay pins 3 and 7?

Second, since the signal from the Stop Lamp Switch goes to the Indicator Relay, won't the beeper beep when he stops?

ak

 

[73's de Edd]

Yes I transposed one number in looking back to schema and then continuing text.
Most likely would be pins 2 and 6 since they involve no brake lights.
So try that combo first.
Having one lead of the Piezo to ground and then it's hot lead to 2. . .to test, and then hot Piezo lead over to 6 to test.

 

[Tim Burchfield]

Yes I transposed one number in looking back to schema and then continuing text.
Most likely would be pins 2 and 6 since they involve no brake lights.
So try that combo first.
Having one lead of the Piezo to ground and then it's hot lead to 2. . .to test, and then hot Piezo lead over to 6 to test.

Edd, thank you for the information. Unfortunately you are dealing with a guy who is an electronics neanderthal. Could you give enough of a description of the piezo so that I could purchase them. I know the function of a piezo but that is about it. Thanks again for the info.

Regards

Tim

 

[Tim Burchfield]

ak

Analog, I must have done something to the flasher. The turns signals still work but terminal P now put out a steady current rather than an on and off current. i.e. the beeper just puts out a steady sound rather than an on and off sound. I ordered a new flasher and will try your suggestion.

Thanks

Tim

 

[73's de Edd]

You say . . .

Could you give enough of a description of the Piezo so that I could purchase them.

I just left off the additional buzzer word portion and that Radio Shack unit you show, is what I am
referring to.
If it is a buzzing when you apply power . . .all is well.
As far as the flasher, you must have grounded its output and crunched the internal power drive
transistor or FET into a shorted condition.
That would account for and produce a non pulsing . . .continual power
output from it.