6v to 12v - turn signals not working


IHC in the early to mid-fifties.

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Post Sat Nov 19, 2022 9:40 am

6v to 12v - turn signals not working

Put in 12v flasher. This truck was completely rewired a couple years before I started the conversion so wiring itself is in really good shape. I used the turn signals for a couple years with the 6v no problems.
Finally got the alternator mounted and wiring jiggered around yesterday. Took it for a good ride yesterday and everything worked well except the turn signals. With the ignition switch on, the battery side of the flasher "box" under the dash lights up in the battery hole. The load hole does nothing whether turn switch is on or off. Not sure if it's supposed to. I'm not sure how to figure out the problem. I bought a 12v 3 prong flasher and I tested that running wire leads from a hot source to X prong and ground wire to L prong and the flasher worked.

Any thoughts on how to test for my issue? Should I open up the turn switch and test that and if I should how should I go about doing it? I didn't mess with the switch at all so I don't know why that would be my problem.
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Post Sat Nov 19, 2022 9:48 am

Re: 6v to 12v - turn signals not working

Do you have brake lights? Do the turn signal lights come on and not flash, or not come on at all? Did you replace the 6v bulbs with incandescent or LED bulbs?

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Post Sat Nov 19, 2022 10:25 am

Re: 6v to 12v - turn signals not working

All other lights work as they are supposed to. The turn signals have their own light housings though if that makes a difference. I kept everything like it was when I got it. So there are two housings on each side in the back and turn signals are on top of fenders in front. I replaced all bulbs with 12v and they were incandescent. The turn lights do not come on at all.
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Post Sat Nov 19, 2022 10:49 am

Re: 6v to 12v - turn signals not working

I'm guessing then that it's an aftermarket setup, and not the integral switch on late R or S series. I'd try just putting 12v to the wire that would be from the flasher to the switch, and then see if you have anything coming out at the switch to whichever side you have turned on, if that makes sense. Would tell you if the problem is in the switch itself.

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Post Sat Nov 19, 2022 11:06 am

Re: 6v to 12v - turn signals not working

Ok I’ll try that but it’s the original switch

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Post Mon Nov 21, 2022 7:38 am

Re: 6v to 12v - turn signals not working

I ended up deciding to throw the 6v flasher back in to see what would happen. The signals worked but extremely slowly so it at least let me know the switch is good. Pulled the 6v flasher out and put the 12v flasher back in and it worked. I had previously taken it out and put back in multiple times. So......no idea what the issue was that it wasn't working before. Didn't change a thing.....but I fixed it :D
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Post Mon Nov 21, 2022 12:24 pm

Re: 6v to 12v - turn signals not working

Some parts just seem to be of the Christian Scientist persuasion and heal themselves. Glad you got it working.

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Post Mon Nov 21, 2022 4:10 pm

Re: 6v to 12v - turn signals not working

I have this thought.
If you are relying on the box and or cab to act as reliable grounds, the lights can be intermittent or fail. I always like to run dedicated ground wire from the light fixtures to the ground circuit at the battery.
Grounding through the body of any vehicle will increase the rate of corrosion. This situation is made worse when the connections get wet from road splash. Road splash is an electrolyte.
There are after-market grounding kits, but this may not be necessary for everyone.
https://www.google.ca/search?q=street+r ... 4&dpr=1.75
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Post Thu Dec 22, 2022 11:36 am

Re: 6v to 12v - turn signals not working

nikkinutshop wrote:I have this thought.
If you are relying on the box and or cab to act as reliable grounds, the lights can be intermittent or fail. I always like to run dedicated ground wire from the light fixtures to the ground circuit at the battery.
Grounding through the body of any vehicle will increase the rate of corrosion. This situation is made worse when the connections get wet from road splash. Road splash is an electrolyte.
There are after-market grounding kits, but this may not be necessary for everyone.
https://www.google.ca/search?q=street+r ... 4&dpr=1.75


I do already have ground wire run to battery. In fact at this point, I have about 18 different ground wires running from everything to everything because I was trying my darnedest to get the 6v to work efficiently.

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Post Thu Dec 22, 2022 4:55 pm

Re: 6v to 12v - turn signals not working

My 6 volt stuff run 12 volt "electronic" flashers the type with a little relay in a plastic "can". I open them up, and take a little tension off the relay spring, and they work just fine on six volt system. Easy to find also.

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