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turn signal odity on my 48 chrysler


harmony

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Recently my right turn signal has mostly stopped flashing on the dash.  Front and back signals are still working on the car, and if I'm looking at the indicator light just as I move the turn signal arm to right turn, I sort of see a faint light right at the beginning but only one flicker.  The arm still automatically cancels the flashing signals once the wheels are straight again.  The left signal flashes strong.  Some of you may not know, but they both use the same light.  So my logical thinking is telling me it must be something in the turn signal mechanism perhaps.  That's the only variable that changes when using the turn signal in respect to that indicator light on the dash.  In order to investigate, it looks like I have to pull the steering wheel in order to get the turn signal cover off.  

There is a chrome inspection type snap in cover on the top of the cover.  Once I took it off there is a slot screw in there.  Does anyone know what that does?  There are several screws on the cover so I shouldn't think it has anything to do with removing the cover.  So I'm guessing it's for adjusting something in the turn signal mechanism ????  Or maybe it is the tightening method for clamping the unit to the steering column.  If someone had a heavy hand, I could see over time the signal unit might start to droop down.  Loosen off the screw and reposition the turn signal unit and retighten the screw.  That actually makes sense.  I was hoping it might have something to do with my issue but that would be far to easy.

 

turnsignal plug.jpg

turnsignal screw.jpg

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This indicates a higher level of resistance in the right hand circuit which causes it to heat the flasher incompletely. Could be carbon on the switch contacts  but I would think more likely a ground at one of the bulb housings or a crusty bayonet socket not making a good connection to the bulb. A poor connection here heats up the instant it's turned on and raises the resistance.

 

I'd just measure with a meter the resistance from power into the switch to out on right and out on left with the signal switched on respectively and compare. Then power in to ground on each right hand signal housing if the first test comes out the same.

Edited by 50mech
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11 minutes ago, 50mech said:

This indicates a higher level of resistance in the right hand circuit which causes it to heat the flasher incompletely. Could be carbon on the switch contacts  but I would think more likely a ground at one of the bulb housings or a crusty bayonet socket not making a good connection to the bulb. A poor connection here heats up the instant it's turned on and raises the resistance.

 

I'd just measure with a meter the resistance from power into the switch to out on right and out on left with the signal switched on respectively and compare. Then power in to ground on each right hand signal housing if the first test comes out the same.

Thanks. I'm just about to convert my turn signals to LED so I'll be checking all the fixtures for ground and corroded sockets etc anyways.  Your diagnoses makes sense, thanks

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Oh yeah, there's an off chance  some barely making connection point could measure fine on resistance if it has to heat up to get resistive....if it all measures good but the problem persists , easiest to hook up test bulbs in test sockets to the signal output. Then you can isolate.

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4 minutes ago, 50mech said:

Oh yeah, there's an off chance  some barely making connection point could measure fine on resistance if it has to heat up to get resistive....if it all measures good but the problem persists , easiest to hook up test bulbs in test sockets to the signal output. Then you can isolate.

Good point.  I have a home made 6 volt test light/socket with alligator clips 

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Do as mech50 says first before the blaming the switch...

The hole with the screw down inside is the T/S SW to column tube  clamp screw .

The steering wheel has to be removed to take the plastic cover off the switch.

Weak failing flashers can also cause this issue of weak or no indicator on the cluster too

Modern replacement 6 volt flashers are Chinese junk and will not work properly!

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So I checked ground on the brass part of the front and back bulbs on the right side and they have a good ground happening.  Plus as I mentioned both front and back right turn signal bulbs both flash.  However I did discover another odity.  At least for me because I simply don't understand electricity very well.  Keep in mind the light on the dash was flashing just fine on both right and left signals up until recently and no changes were made.

The car was parked and I think just perhaps by mistake I put the right turn signal on and it flashed just fine on the dash.    As I went for a drive it went back to not indicating on the dash.....  Parked the car, tried it again and it was flashing on the dash again.  That's when I realized that once the parking brake was applied, the indicator would flash.  As some of you may or may not know, the parking brake has a flashing light when it is engaged once the car is running, as a warning that the hand brake is applied. 

 

Does this new twist make it any easier to diagnose?  Is it perhaps a matter of just cleaning the contacts on the flasher as well as on the sender switch for the hand brake?  If so, why?

I really didn't understand Mech50's comment ,,,, "a higher level of resistance in the right hand circuit which causes it to heat the flasher incompletely"

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Same deal, just another indication that the right hand circuit has high resistance somewhere.

With the park brake activating the flasher it's able to heat and switch all the way. So now the right signals don't have to draw the minimum current to properly operate the flasher correctly..there's already a device drawing it.

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2 hours ago, 50mech said:

Same deal, just another indication that the right hand circuit has high resistance somewhere.

With the park brake activating the flasher it's able to heat and switch all the way. So now the right signals don't have to draw the minimum current to properly operate the flasher correctly..there's already a device drawing it.

I'm still not clear on what's going on, so where would I be looking for the problem?  Like I said both front and back right turn signals are working just fine?

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Here's a flasher internals.

The p terminal lights your indicator, its the same for left,right,parking.

The load ( turn signal) completes the circuit that runs the heater. The bimetal strip then moves toward making contact until it does, that shorts the heater out of the circuit and the bi metal cools, bends back and breaks contact.

 

Since the p terminal is working for the other circuits it indicates the right hand turn signal is likely not giving full power to the heater so contact with the p terminal is never completed.

 

A different flasher may solve the problem at least for a while as it may not be so sensitive to the lowered current. An electronic flasher would certainly solve it.

 

Something in the right hand circuit is offering too much resistance. Common points would be body grounds, junction blocks, bulb sockets, switch contacts.

 

You could use a long jumper clipped to battery ground and to the signal housing s. If it makes no difference you've eliminated all grounds as a problem.

 

You could unplug the signals and hook up two bulbs parallel directly after the switch, if it makes no difference you've narrowed it to the switch.

 

Neither of those work you could use your long jumper from the power out of the switch to different points along the signal circuit. When you've bypassed the problem area it will work again.

 

fl_test (1).gif

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On 8/24/2020 at 8:43 PM, Dodgeb4ya said:

Do as mech50 says first before the blaming the switch...

The hole with the screw down inside is the T/S SW to column tube  clamp screw .

The steering wheel has to be removed to take the plastic cover off the switch.

Weak failing flashers can also cause this issue of weak or no indicator on the cluster too

Modern replacement 6 volt flashers are Chinese junk and will not work properly!

The flasher I got from LEDlight.com is made in Taiwan.  p/n 84787.  

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7 hours ago, 50mech said:

Here's a flasher internals.

The p terminal lights your indicator, its the same for left,right,parking.

The load ( turn signal) completes the circuit that runs the heater. The bimetal strip then moves toward making contact until it does, that shorts the heater out of the circuit and the bi metal cools, bends back and breaks contact.

 

Since the p terminal is working for the other circuits it indicates the right hand turn signal is likely not giving full power to the heater so contact with the p terminal is never completed.

 

A different flasher may solve the problem at least for a while as it may not be so sensitive to the lowered current. An electronic flasher would certainly solve it.

 

Something in the right hand circuit is offering too much resistance. Common points would be body grounds, junction blocks, bulb sockets, switch contacts.

 

You could use a long jumper clipped to battery ground and to the signal housing s. If it makes no difference you've eliminated all grounds as a problem.

 

You could unplug the signals and hook up two bulbs parallel directly after the switch, if it makes no difference you've narrowed it to the switch.

 

Neither of those work you could use your long jumper from the power out of the switch to different points along the signal circuit. When you've bypassed the problem area it will work again.

 

fl_test (1).gif

Thank you for that comprehensive explanation.  I'll follow your advice in the order you suggested and I'm bound to track down the problem.  I have a parts car, so I can try replacing the switch if necessary. 

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I tried a long wire with alligator clips on both ends.  One end on the battery ground and the other on the sockets, front and back.  I still didn't get the pilot light to flash.  

Since I am just about to do the LED conversion for the running lights, amonst all the goodies, I had ordered a 6 volt positive ground electronic flasher.  So it was a fast and easy swap to give it a try.  That did the trick and the pilot light now flashes both right and left.

 

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