VCCA Home Forums TECHNICAL - GENERAL Electrical - 6 volt Turn signal problem

For some reason the turn signal indicator on my car faintly lights up all the time when the engine is running. . The indicator bulb was changed to an LED bulb when I added the directionals a few years ago and this just recently started. Sometimes when applied the lights at first flash erratically (FAST) and the a constant steady fast flash. I did try a couple of different flashers with the same result. Also used a separate second battery for running power to bypass possible generator causes and it was no different. I do have a Peterson regulator on the generator and LED tail lights along with LED headlamps. I did switch the headlamp bulbs back to std but no difference. My friend that is helping me did check with a multimeter and somehow there is a .3 milliamp a/c feed back. If anyone has any ideas on what the problem may be I would love to know.

Often times when we saw a dim light in a circuit it that wasn’t actually being used it was caused by a poor ground and the back feed of current would light something dim. The most common we saw was a turn signal indicator would light dim when the lights were turned on and you had a poor ground in a tail light.

Can you easily/neatly disconnect each bulb one at a time? I've seen incandescent bulbs short partially between filaments and/or ground. LED's are solid semiconductors so they too can partially fail in unique ways causing this.

Since you have a means of measuring and reproducing the 0.3ma feedback, you can disconnect one lamp at a time and see if you can eliminate this 0.3ma. One at a time keeps the troubleshooting clean and organized but maybe pulling several LED's if they are socketed at the same time might help you decide if it's the LED side or the incandescent side causing the problem.

Thanks dens41 for the reply. This happens even when all lights are off or on . All lights are normal when turned on-headlamps-park lamps-tail lights-brake lights-and the turn signals. And now that I posted that I remember that the dash lamp is not working so will check to see if that may be the source. The dash lighting has been bypassed-see the following post.

We did disconnect the POS wire to the coil and ran a jumper from a separate battery to the coil (hot wired). That basically eliminated all the wiring except the ignition circuit. Later this week we will hook it up to an oscilloscope and see if that shows anything.

I thought you might be on track with the dash lamp being out. Grounded or shorted bulb does some wonky stuff so any bulb acting strange is the best first target.

Scope is useful for measuring small AC or noise,though if small AC is an issue, it's pretty much a given that the LED electronics are the issue as everything else is DC. If you still have the original bulbs, might be an idea to swap out the LED and see what you see.

You seem strong at troubleshooting so I'm sure you'll find it and get a laugh out of what it turns out to be!

My biggest strength is having a good friend who has the knowledge and equipment and tools to get the job done. He retired from a local city working in the traffic dept.and then spent five years in a resto shop doing mechanical and electrical repair. We do a lot of various projects together automotive and household and enjoy working with each other and when the jobs done we both enjoy a good brew.

Today we spent a couple hours looking for the turn signal gremlin and did not find him. However we did find a bad rotor and cap so those were changed but no difference in the turn signal problem. I have no idea how the car still ran but we found the spring arm on the rotor completely separated . When the rotor was removed it fell out. Photo attached. The contacts inside the cap were carboned over so I opened my NOS spare and while the inner contacts were perfect the plug wire sockets were tarnished. Cleaned those with the bead blaster and installed but it made no difference to the turn signal problem. Will go back at it on another day.

Lucky find. It's a good thing you travel with a spare.
I just had a NOS rotor fall apart. The whole metal contact fell off when I pulled it from the box.
Hopefully your brain kept working on the signal problem while you slept last night and you awoke with the solution...

I just re-read your original post. I wonder if the LED bulb has created the problem if you are using a conventional flasher.

I have heard of may cases when the low current draw of a LED bulb will not be enough to create the magnetic field that a conventional flasher requires. The solution is to convert to an electronic flasher or add a dummy load.

Indeed lucky and I will definitely get a new spare. Rusty 37 we did add a dummy load (headlamp bulb) and it made no difference.

Thanks for the confirmation. Just trying to think of solutions.

Do you have the same behavior if the all the bulbs are conventional filament bulbs?

My tail lights are LED and I have had no problems until recently. I have a couple of things I will check this weekend.

I have not found the source of my problem but using carbon core wire from dist. to coil has eliminated the constant directional signal flashing. The turn signals work fine so I am satisfied with it as it is.

Hi Steve are you Running 6 or 12 volt System on you car

I am running 6 volt. I have Lambert LED tail lamp conversions and a Peterson regulator on the generator. The front turn signal is built in to the headlamp park bulb (incandescent for load) (changed to dual pigtail). The turn signal switch is a United Pacific A5007 w/o emergency flashers. All lights work fine except the dash lamp due to a corroded socket holder on the instrument panel. Still trying to find a way to clean it without removing it-not the easiest place to reach.

had to clean mine as well, dash bulb would not work , thought it wasthe bulb till i changed it a few times, and then did a hot wire of the bulb socket.

i used a piece of sandpaper wrapped around a small piece of pex. small piece of tape to hold it on the pex. reached up under the dash, slid the sandpaper end of pex in the socket and worked it for a few. this worked great. make sure you remove the dash bulb and socket. i also cleaned up the inside and outside of the bulb socket.

what kind of wire were you using ?? i am using a set i got from Bob Marx at Marx Parts, custom made set. all 7 of my wires are the same type, just various lengths :)

My wire is black lacquer copper core . Not sure where I got it but may have been Marx Parts as I did purchase some items from him. My spare rotor was one of those items, though I did find three used ones in my attic. We put a rolled up bounty towel in Evapo-Rust and stuffed it in the socket holder and left it over night. I removed it today and cleaned the surface with a plumbers pipe cleaner. Instruments now are lighted. We also did the sandpaper trick first but I wanted to be able to get in the groove of the holder.

Hi Steve the reason I asked if your car is 6 volts.You posted that you have used a carbon core High Tension Lead. I have had a lot of problems with my 34 it was missing and backfiring back through the carburetor. I tried everything from my 60 year mechanical experience, plus all the input from local experts to find the cause. I tried different reconditioned carburetors both Carter W1 and Rochester, new coil, plus two overhauled distributor's, plus several sets of spark plugs, swapping points, rotors, condenser's,. .. distributor caps plus high tension leads. My original leads were carbon core suppressor type so I replaced them with a set of local Bosch pre-made HT leads. But the engine still kept misbehaving. In desperation I turned to Mr. Google an find a article on the Filling Station web site stating that YOU CAN NOT USE SUPPRESSOR TYPE LEADS ON 6 VOLT. I had never heard of this so I made up a set of copper cored leads and to my astonishment the engine runs like a new born baby.
I don't think this will help your turning signal problem but if your engine develops any misfiring it might be worth remembering.
Regards Paul Mitchell

Thanks for the heads up Paul. I did put the copper core removed lead in my travel bag as a precaution.

Hi Steve,

Is it possible there may be a "rubbed" wire in the directional switch itself or the switch lost ground ??

The ground is good. Not sure about the rubbed wire but that is a possibility as it now only happens when the switch stalk is moved from the off position to activated. Once engaged in the operating position everything is fine. Previously to changing the coil HT wire the indicator constantly flashed. Now it only does it when between stops .

I found it interesting that you found the rotor falling apart and a solution involving the coil wire. Makes me wonder if something is failing in that area, like a sloppy dist shaft, poor condenser, poor dist ground, or ill-fitting distributor cap causing some noise which wasn't there before. Of course it may not take much noise to cause weird problems with modern electronics.

I ran an Oscilloscope years ago in a car for a short while just for the heck of it and it was common to see electrical noise spikes double and triple the battery voltage. Was pretty easy to understand radios needing filter capacitors.

My last trip with the car was over 100 miles and it never missed a beat. When we pulled the cap off the distributor the rotor literally fell apart. It's a wonder it even ran. The scope showed a double fire spike on all cylinders and that's why we pulled the cap. The cap internally was the blackest I have seen yet there was no pitting on the end of the rotor and non on the terminals inside the cap. The distributor shaft has no play and the ground is fine. Both cap and rotor were new when the engine was rebuilt and they had about 12000 miles on them. A couple years ago I had an overheating problem and I think it may have been the rotor was cracked then and causing it to have retarded timing. We bumped the timing up and it has run fine since then with no overheating. With a NOS cap and new rotor we set the timing by ear and it ran over half an hour while sitting and the temp never went past halfway so I think it is good to go. The six cyl. tour is in a couple weeks so it will get tested.