LED light bulbs

[JimD]

I wanted to experiment with the LED replacement bulbs that have become available because the "instant-on" characteristic of LEDs really catches the

eye of the driver behind you.

My 1998 Seville body style has a separate, single-function, amber turn signal lamp on the rear, and that is where I started.

The OEM incandescent bulb is a 3057 (yes, a double filament bulb) and the LED replacement is a 3157. Purchase bulbs with the maximum number of LEDs;

I have recently seen as many as 25 LEDs in the 3157 package (more is better).

Be sure to use amber LED bulbs when dealing with an amber lens and red LED bulbs when dealing with a red lens. White or clear LED bulbs have too much blue spectrum; it's just the nature of the beast.

There is a GOTCHA. The LED bulb does not pull enough current to satisfy the flasher module. You could change out the flasher module (difficult to get to) or, use a high wattage resistance to simulate the load of an incandescent bulb.

I elected to 'simulate' and used two (2) 10 ohm, 10 watt wirewound resistors in parallel to obtain 5 ohms. Connect this 5 ohm resistor package between the two wires going to the socket (or, between the 'light blue' wire and a convenient chassis ground).

Be sure to attach the body of the resistor(s) to the vehicle for heat sinking; the resistor(s) are dissipating quite a bit of (heat) energy. And the mounting screw for the resistors is a "convenient chassis ground".

LED bulbs are by their nature 'polarized'. If the bulb fails to light up when you think it should, just rotate the bulb 180 degrees in the socket and try again.

Be sure to insulate and waterproof your connections.

Now do the other side.

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There are many sources of LED replacement bulbs; here are two:

http://www.autolumination.com/

http://www.superbrightleds.com/

Radio Shack has the 10 ohm, 10 watt resistors.

Have fun.

[Logan]

These guys are considered the 'cadillac' of LED bulbs...vs the China ones at AutoZone etc.

www.ledtronics.com

[JimD]

In the two years since my original post, there has been significant development in LED technology as applied to aftermarket automotive lighting. The LED bulbs available today are at least as bright as an incandescent bulb in the same application.

I am currently using amber LED replacements in my rear turn signal lamps from the following location; http://autolumination.com/3157_3156.htm. Their "Eagle-Eye Tower" bulb is nothing short of fantastic; very bright and has excellent off-center viewing angle coverage.

The rear turn signal application in post #1 is perfect for '98 - '04 Sevilles. If anyone needs pictures or more details, I would be happy to help. It is necessary to use a load resistor as the turn signal flasher is combined with the hazard flasher and an aftermarket electronic flasher replacement will not work.