Re: LED Lights
Posted by HH56 On 2024/6/6 13:30:50
If you mean rear tail lights instead of rear park lights, those use a separate filament and are fed directly from the headlight switch. They are on both with park and with headlights and should not be affected in any fashion by the turn signals unless there is some kind of tie inside the new LED bulbs. Ground is the only thing the incandescent bulb filaments share. If tail lights are flashing I suspect it is because there is a faulty ground and the turn signals are trying to find a ground somewhere else in the car by going thru shared tail light wiring and filaments to another bulb which is in parallel. Another possibility is the LED bulb construction. If some other light is flashing in the rear please identify what you are calling a park light.
A full electronic flasher should work all LED bulbs without any kind of restriction or extra resistance needed. Those come in both positive and negative ground versions. If you replaced the original flasher with a modern 535 which is sold as being a universal replacement for the old flashers, those are negative ground, also part thermal so somewhat filament dependent, and are partially electronic with a transistor driving the indicator lights. They will work the stock turn signal bulbs but because of the polarity issue will not work the dash indicator lights.
You have probably seen this drawing before but here is a synopsis of the turn signal circuit. When the lever is moved, the front and rear outside bulb turn signal/brake filaments are simultaneously connected to the flasher. That connects the flasher to ground thru the filaments so both bulbs start flashing. Note that ground is provided thru the bulb shell to park or tail light housing with the tail light and park filaments being powered from a totally separate source coming from the headlight sw. At the same time the rear bulb is connected to the flasher, it is disconnected from the brake light circuit so that the constant power if brakes are applied cannot keep the filament from flashing.
I think the first thing to verify is the ground situation and make sure the new LED bulbs have the same function separation as the incandescents. If they are a universal non polarity specific bulb, make sure there is no leakage to the other filament (or in this case, LED) thru the internal circuitry that ensures the polarity reaching the actual LED is the same all the time. That might need you to discuss your problem with the supplier of the LEDS.
Attach file:
49-56 Turn Signal Extraction2.jpg (724.10 KB)
A full electronic flasher should work all LED bulbs without any kind of restriction or extra resistance needed. Those come in both positive and negative ground versions. If you replaced the original flasher with a modern 535 which is sold as being a universal replacement for the old flashers, those are negative ground, also part thermal so somewhat filament dependent, and are partially electronic with a transistor driving the indicator lights. They will work the stock turn signal bulbs but because of the polarity issue will not work the dash indicator lights.
You have probably seen this drawing before but here is a synopsis of the turn signal circuit. When the lever is moved, the front and rear outside bulb turn signal/brake filaments are simultaneously connected to the flasher. That connects the flasher to ground thru the filaments so both bulbs start flashing. Note that ground is provided thru the bulb shell to park or tail light housing with the tail light and park filaments being powered from a totally separate source coming from the headlight sw. At the same time the rear bulb is connected to the flasher, it is disconnected from the brake light circuit so that the constant power if brakes are applied cannot keep the filament from flashing.
I think the first thing to verify is the ground situation and make sure the new LED bulbs have the same function separation as the incandescents. If they are a universal non polarity specific bulb, make sure there is no leakage to the other filament (or in this case, LED) thru the internal circuitry that ensures the polarity reaching the actual LED is the same all the time. That might need you to discuss your problem with the supplier of the LEDS.
Attach file:
49-56 Turn Signal Extraction2.jpg (724.10 KB)
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