Checking out my car before upcoming road trip and I discovered no turn signals with the headlights on. They work fine without. Emergency Flashers and parking lights both are functional. Dashboard indicators also work just fine as do all the functions of the tail lights. Everything worked a year ago when I passed an NSRA safety inspection . With the dash indicators working there’s no telling how long the problem has existed without my knowledge .. The bulbs are non-traditional LED units front and rear. I tried a new flasher which did not solve. I have a GM style headlight switch, parking,head and dimmer of dash lights functions, Any ideas on how to approach at this point?
if the headlights and turn signals get ground from the same place, check that.... otherwise, put normal light bulbs in. And if it still doesn't work, at least it'll be traditional.
For clarification, do the emergency flashers and the dash indicators work with the headlights on? I’ve never experienced an NSRA safety inspection. Did they test the turn signals with the headlights on?
Yes,test with headlights on, and flashers and indicators both work with the headlights on. Tail lights work in all situations.
I'm starting to doubt that the "safety inspector" checked the turn signal with both headlights on and headlights off. My first guess is your signal lamps are also running lights and are getting uninterrupted power when the headlights are on. It could be something else but that's what I would check first.
Do the brake lights work with the headlights on? It is possible that the turn and taillights are wired together and the brake lights are on the separate circuit. It should be the brake and turn signals using the same bulbs and the tail lights on a separate circuit. Just a thought. Edit: Another possibility is the ground for the flasher unit could be connected to the headlight circuit. If the ground becomes energized it won't allow the flasher to flash. Try disconnecting it from it's current ground and ground it directly to the battery or possibly the frame.
Squirrel hit it on the head. As these are two separate circuits, the only commonality between them would be grounding, so that's where to look. That could include the headlights being mis-wired with the ground and one hot being switched to the headlights.
Last year I updated my 64 Marauder to led taillight and turn signal bulbs and electronic flashers. They worked great at first. I did it just before the Back to the 50s in Minnesota. Halfway from Wisconsin Dells they started acting up and I spent half the trip messing with connection and talking to the wiring guys displaying at the event. There answer was to buy their set ups. by the time I got back I had fried my turn signal switch, Replaced the switch and put conventional bulbs and flashers back in and problem solve. Evidently on some cars you also need some other resistor type unit wired into the harness that prevent the bulbs from back feeding through the system. Checked and clean all the connections I could and put everything back to OEM and it has worked fine since. I talk to alot of people since then and some the updates work fine and others it is a crap shoot. It is most likely searching for grounf or the hd light switch or the trun signal switch are back feeding through the switches. cost me over 200,00in new parts witch have I tossed. should have left it be. best of luck, Larry
I would say Ground , like mention,. Did you happen to change the head light switch ? I have found there are Headlight switch that are sold as pre 68 But missing terminal spades , & pin wrong ...
AS Steve said, if it is wired correctly and hooked up correctly the only issue should be that the turn lights aren't going to ground correctly. If it is those goofy looking lights that I think they are the park/turn leds ground though the same ground wire that the headlight uses and their ground wire is tied into the head light ground wire inside the housing. If you are using a bulb assembly like this one there is no frigging PARK LIGHT function and if you have one of those wires connected to the head light circuit to operate as park lights that is the issue. They are Turn signal only with red to the switch black to ground.
Searching some more, these with the amber turn light have the amber as turn only and not park. some seaching shows that all the bulbs I can find with built in turn signal led or the amber bulbs do not have any sort of park light function.
I have to agree with Squirrel, a friend of mine put LED's in his Forty and everything works great until you start the car and then the turn signals won't work, I checked every connection including the grounds, put in an electronic flasher, even added a resistor in parallel to create more load on the flasher and never did get them to work.
As it turns out after checking with a friend of mine who has a lot of wiring experience he finally asked me if parking lights were dimmer than when the turn signals or flashers were in use. Long story short the leads coming off the parking/flasher assembly were reversed, the ground was not the problem. Three of us still scratching our heads as to why/what the headlights being on/off dictated whether the turn signals worked or not. Solution found, thanks to all who responded.
I'll bet your light switch leaves the 'park' lights on when the headlights are on. With the leads reversed on the park/turn lamps, the dimmer park lights won't show as 'flashing' when the headlights are on.
For the most part, LED light fixtures have 2 sets of different wattage individual LED elements. The turn signals are suppose to use higher wattage set of LED elements within the light fixtures and the parking light set of LED elements are suppose to use lower wattage sets within the light fixtures. The higher wattage sets of LED elements within the light fixture are brighter then the lower wattage sets LED elements in the light fixture. Both sets of the different wattage LED elements use the same ground wire circuit. If the wiring through the LED fixture is not marked, color coded, or labeled correctly (I've seen it many times before), the wiring with in the light fixture has the wires to the wrong sets of LED elements. The wire marked as the "turn signal" actually powers the lower wattage parking light circuit through the light fixture. The wiring marked as the "parking light" actually powers the higher wattage turn signal circuit through the light fixture. With the incorrect wiring through the LED light fixture, when the headlights are on, (the headlight switch also operates the parking lights through the switch) the parking light power from the car is actually powering the higher wattage and brighter "turn signal" circuit through the fixture. The turn signal car wiring from the car is actually using the lower wattage (and less bright) "parking light" circuit of the LED light fixture. The turn signals would still flash (the reason they show they work on the dash and the tail lights operate correctly), but won't be bright enough to see over the brighter parking light elements in the front light fixtures. Turn off the headlights (and parking lights), and the lower wattage elements within the light fixture that are now the "turn signals" can now be seen. I've encountered this enough with the modern LED lights, I always test the wiring in the LED fixtures to be sure the wiring is correct. I have never encountered the ground wire being incorrect, but the high and low voltage circuits have been exchanged several times. Simply wire the brighter elements to the turn signal power source and a lot of issues have been solved.
When I wired my dash, I used LEDs for the high beam indicator, turn signal indicators and dash lights. At first, my only problem was the front park lights wouldn't work at the same time and the turn signal indicators in the dash would be on dim when the headlights were turned on. I figured that if I added a ground wire to the instrument cluster would clear up but it hasn't. Would love to go back to old style incandescent bulbs but at this point that would be very difficult. Just keep plugging away at it.
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