bulb to LED taillight conversion

[bluegrasser]

I'm posting this for a friend who does not have internet access. Here's the problem. His 2008 C class had 2 Bargman tail lights on each side plus a backup light. With lights on, all four light up. With brake application, all four light up at increased brightness. With turn signal use, the appropriate two light either come on, or show increased brightness if the lights are on. All this is how it should work. Now a simple swap of Bargman incandescent tail lights to Bargman LED tail lights. First problem, the new units flash very quickly on turn signals. We suspect the flasher is not big enough, so it is changed to a heavy duty flasher. One flash and the fuse (15amp) blows. We are reluctant to up the fuse to 20 amp., we're not sure if the wiring will take 20 amp. The Bargman LED tail lights have 16 LEDs in each unit, meaning that 32 LEDs are flashing with the turn signals, 4 way hazard flashers have 64 LEDs flashing at the rear. We're not sure how to correct this problem, any help would be appreciated.

[bluegrasser]

I'm posting this for a friend who does not have internet access. Here's the problem. His 2008 C class had 2 Bargman tail lights on each side plus a backup light. With lights on, all four light up. With brake application, all four light up at increased brightness. With turn signal use, the appropriate two light either come on, or show increased brightness if the lights are on. All this is how it should work. Now a simple swap of Bargman incandescent tail lights to Bargman LED tail lights. First problem, the new units flash very quickly on turn signals. We suspect the flasher is not big enough, so it is changed to a heavy duty flasher. One flash and the fuse (15amp) blows. We are reluctant to up the fuse to 20 amp., we're not sure if the wiring will take 20 amp. The Bargman LED tail lights have 16 LEDs in each unit, meaning that 32 LEDs are flashing with the turn signals, 4 way hazard flashers have 64 LEDs flashing at the rear. We're not sure how to correct this problem, any help would be appreciated.

[John90XJ]

It seems like you actually did the reverse of what you should have done. With a large number of LEDs, you need a non-thermal flasher and having added the heavy duty unit makes it even harder for the very low power LEDs to work. Try putting in an LED specific flasher and seeing if that resolves the problem.

I've added LED taillights to my Jeep and the stock flasher was adequate because the resistance from all the other incandescent bulbs in the system allowed the flasher to continue working. Having more LEDs than not will require the LED specific flasher.

I have no connection to this company but here is a link to what you likely need:

http://www.v-leds.com/Shop/Control/P...id/0/SFV/32481

[bluegrasser]

Thanks John90xj. Some of this is now starting to make sense. Next question, would the LED specific flasher be able to handle the stock incandescent bulbs in the front signals? I will check with some auto electric supply outlets here in Canada to see what is available locally.

Once again thanks for the info, I will post the results so anyone else doing this mod will have a starting point. I converted my own lights on the old 89 GM chassis and it was a simple plug in swap. I guess back in 89 we didn't have all the modern sophisticated stuff to deal with.

[John90XJ]

I would hope the electronic flasher can handle all the duties. It's basically replacing a thermal contact point with solid state, so it should be fine. The difference is really one of cost. The thermal ones are practically free, the others obviously more expensive.

I'm running 4 incandescent bulbs on my Jeep (corner markers and turn signal/park lamps) and then the LED S/T/Ts in the rear and the regular light duty thermal flasher works fine. However, I have friends that had to swap it out of they had separate LED stop/tail and turn lamps. Apparently there wasn't enough there to work them correctly.

I recently bought a tow dolly with all LED lighting on it and it should be interesting to see how it performs since none of my coach lighting is LED. I may be seeing the same problems here in the next week or so.

[NeilV]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by John90XJ:
I would hope the electronic flasher can handle all the duties. It's basically replacing a thermal contact point with solid state, so it should be fine. The difference is really one of cost. The thermal ones are practically free, the others obviously more expensive.

I'm running 4 incandescent bulbs on my Jeep (corner markers and turn signal/park lamps) and then the LED S/T/Ts in the rear and the regular light duty thermal flasher works fine. However, I have friends that had to swap it out of they had separate LED stop/tail and turn lamps. Apparently there wasn't enough there to work them correctly.

I recently bought a tow dolly with all LED lighting on it and it should be interesting to see how it performs since none of my coach lighting is LED. I may be seeing the same problems here in the next week or so. </div></BLOCKQUOTE>

The standard duty thermal flasher works by the heat created by the high electrical load of the fillament type bulbs in the circuit. When you replace the bulbs with LED's, since they don't draw as much current, the thermal strip in the flasher does not heat up as fast and the flashers will slow down or stop altogether. This feature is what would alert you that your bulbs were burnt out as a burned out bulb draws no current.

The heavy duty flasher still uses the heat strip but it is not wired the same way so the load of the bulbs does not pass through it. That way it flashes at a consistent speed regardless of the load up to its rated capacity. If you have an overdraw or a short in the system since it does not flash or break the circuit faster due to the increased load it will blow the fuse more quickly than the standard flasher.

The electronic flasher has a timer instead of the thermal strip and will flash at its set speed regardless of the load up to its rated capacity.

If you change to LED bulbs and a thermal flasher speeds up instead of slowing down then there is a possibility that a short circuit has been introduced into the system or something has been cross wired. Blown fuses or total failure of the electronic flasher could occur in the event of the dead short.

Since Sandy's friend has blown fuses once switching to the heavy duty flasher I would suspect that the plugs on the new LED lamps while similar to the original may not be fully compatible in the way they are wired. The veicle could also be one with a positive ground but that is not that common.

[bluegrasser]

Thanks Neilv: The original problem with the fast flashing tells me that the new LED lights were drawing more current than the old filament types. Anytime I have added lights to a flasher circuit the flash rate increased due to extra load and required a heavy duty flasher to bring the rate back to normal. I would think that even though there are a lot of LEDs they would still draw less than the filament type bulbs. The new lights are pre-wired with a plug that fits the existing bulb sockets. We will remove the lights and re-install them one by one which should give some indication of whether or not any of them have a short or wiring problem. I can also temporarily swap in a couple of mine to test the setup. It seemed strange to me that all four units flashed together on hazard or two on turn settings. My turn/hazards are amber with a 2 wire circuit, while all 4 of Jerry's are all red with 3 wire circuits. I have done a quick search on the electronic flashers and they appear to be 2 pin while the originals are 3 pin. The plot thickens! How did such a simple thing become so complicated. Thanks for all the help so far, I will keep you posted on the progres

[dirko]

Hi Ho: My experience with electronic things is that most of the intermittant problems are caused by connectors, switches, or relays that are intermittant. You might try WD 40 on the connector where it gets exposed to water and make sure the connections are clean and tight.

Good luck, Dirk

[jrcnlc]

I bought two 1157 led bulbs red for trailer.I installed one to see if brighter than standard bulb an its dimmer.Mabie i should have bought white leds?Now i have two extra bulbs.