Turn signal goes out at "high" load

[Darth]

Hello folks

I have bought my first US car ('71 Dart, stock 318) a few months ago and currently just enjoy driving it around. As temperatures started to drop I found out that

• heater works (... there is a slight temperature increase after 15 minutes of driving... )
• heater fans work
• all lights work (except for the dash, but I messed them up after messing around with an aftermarket tach)

All seems well, BUT, when its all on, as they usually are on a cold, dark morning like today and I roll in stop and go traffic, the turn signal will only blink very slowly. It doesent go on and off at the usual ~1 second interval but 2-4 seconds at an irregular pace. Twice it went out entirely but came on as soon as I started accelerating a little bit.

Before I start looking for problems where there are none: is the above behavior normal or is there something wrong with some part of the car?

 

[memike]

Have you tried changing the small round flasher under the dash, it may be your problem Darth

 

[RedFish]

At a stop or idling in gear and very low rpm, the system voltage can fall below 12 volts. This causes headlights to dim, blower and/or wipers to slow, and even turn signals could slow to a stop.
If none of the other symptoms exist, replace the signal flasher.

 

[68gtxman]

I agree with Redfish. Plus, a modern voltage regulator may solve your problem too. The electronic voltage regulators do a much better job at keeping the alternator's output at 12.5 volts or higher, even if the engine's idle RPMs remain the same. If you already have an electronic VR, then check the ground contact on it and clean it up. If that doesn't work, raise your idle just a tad.

Oh and welcome to MOPAR's!

 

[Darth]

At a stop or idling in gear and very low rpm, the system voltage can fall below 12 volts. This causes headlights to dim, blower and/or wipers to slow, and even turn signals could slow to a stop.
If none of the other symptoms exist, replace the signal flasher.

No other part is affected (blower, headlights, wipers all run as they always do). Hmm, will go flasher hunting in this case.

@68gtxman: I don't know if the voltage regulator has been upgraded by the previous owner(s). As I'm quite new to this, how would I indentify it? Oh and thanks for the welcome! ;)

Cheers!

 

[68gtxman]

Mechanical VR (though to know for sure, you need to look under the black cover. If you see a coil there, it truly is a mechanical unit.)

Electronic VR

 

[RedFish]

No other part is affected (blower, headlights, wipers all run as they always do). Hmm, will go flasher hunting in this case.

@68gtxman: I don't know if the voltage regulator has been upgraded by the previous owner(s). As I'm quite new to this, how would I indentify it? Oh and thanks for the welcome! ;)

Cheers!

There are 2 flasher modules. The one mounted on the steering column support ( easiest accessed ) is for emergency flashers. The one for turn signals is mounted on the right hand side of the ash tray hanger.
Early on the flasher module was metal bodied and held in a metal clamp. Later models got a plastic bodied flasher ( light blue plastic was OEM ), so if you removed the ash tray and look at the right inner side of that hanger you could see a small light blue square. That is a tab atop the flasher that pokes through a opening. The flasher was then rotated 90 degrees to create a metal on plastic bite there.
I honestly don't know what year model this changed.
I guess I would go ahead and try a new flasher first. If that doesn't cure it, system voltage is the culprit. Once that is fixed, everything about the cars electrical will work better. You might even get better fuel mileage.

 

[TrailBeast]

No other part is affected (blower, headlights, wipers all run as they always do). Hmm, will go flasher hunting in this case.

@68gtxman: I don't know if the voltage regulator has been upgraded by the previous owner(s). As I'm quite new to this, how would I indentify it? Oh and thanks for the welcome! ;)

Cheers!

Do yourself a favor and get the electronic flasher.
They don't slow down when the voltage drops, because they don't rely on load and voltage to flash.

You won't be sorry.