LED Bulbs

[67MercM100]

Does anyone have any knowledge of or experience with LED Bulbs?

I bought a pair to use in my tail lights and I'm having a hell of a time.

The backstory is that all the wires to the tail lights (and backup lights) were cut and gone from just behind the two "plug in" connectors under the bed. I've wired things back up. Tail lights: check; Brake lights: check; Left blinker: check; Right blinker: works OK - BUT the left tail light blinks. Not the bright brake/turn light; the tail light.

Rechecked my wiring. Put new contacts in the left socket and cleaned up some paint overspray from inside the socket. Reconnected the wires. Tested it with the tail light housing not screwed into the body using a spare piece of wire. It was OK, so I re-attached it to the body. Did the same thing on the right. Everything was fine - up until I re-attached the housing to the body. Then it was back to the same thing.

Maybe one of the LEDs isn't quite right, I thought. But swapping them made no difference.

Just for fun, I traded the LED in the right with a regular 1157 bulb. Now it all works OK!! I messed around with different combinations of LEDs and 1157s with the right housing both attached and grounded with just a wire. Now I can actually get the "opposite tail light blink syndrome" on both sides when I have LEDs in both sides. Everything clears up as soon as I put one 1157 in.

The only thing that I can figure is that somehow, somtimes the "brake" side of the LEDs sometimes transmits power back through the "tail light" side. Since that's essentially one wire that splits, the power gets back to the other side.

Does anyone have any explanation?? Obviously the answer is to run the 1157s and put the lenses on. But since it's still a work in progress, it would be nice to have the red LEDs just so I didn't have to mess with the lenses for now. (Plus I was hoping the LEDs would look kind of cool even through the lenses when everything is all done.)

[knightfire83]

Sounds like bad ground connections on the sockets or the tail light to body connection. If the ground isnt good enough the bulbs will ground out to the other bulbs via the tail light circuit.

The leds take very little current to function.

When you put a 1157 bulb in, the led is still sending current (grounding) to the taillight circuit, just not enough to light the 1157 taillight filament on the opposite side.

If you put both 1157's in the rear it should also have the "opposite tail light blink syndrome."

You can roll up a section of sandpaper into a tube and clean out the sockets. You also may want to check where the tail light housing contacts the body for a ground, and the mounting screws.

[Thunderfoot]

Also, check the ground connection on the Left side even though it seems to be working, bad grounds do strange things... It does seem like a grounding issue...

[fordman]

are the led bulbs slightly shorter than the 1157? could it be they need more power to run them. i thought the led required more power to them or a realy to make them work . i read about doing something to use leds in a instrument cluster.

[fordman]

yea and then the traffic lights wont unthaw the snow and ice from them.

[ForingaMex]

Gain some, loose some.

[67MercM100]

Thanks everyone. For now it's OK with "regular" 1157s in both sides. It probably is a ground issue. The housings have some paint overspray in and on them. (previous owner...I certainly wouldn't do that)