Need Help hooking up LED lights.

rdfeatherstone · 08-31-2005, 02:58 AM

Hi,
I want to mount some LED lights to my Big Tow mirrors. The LEDs are to be hooked up to the turn signals so that when I turn on the left hand turn signal, the LED mounted on the left mirror will flash at the same time as the OEM turnsignals.

Can I just "Piggy-back" them into the turnsignal circuit, or do I need a separate flasher and/or resistor in the circuit??

Any help is appreciated.

Ralph

f00dstamps · 08-31-2005, 05:02 AM

typically, the current draw from the LED's will not be enough to trip the lighting fuse. you should be able to just tap into the turn signal directly. however, if you wanted it to be independent, you should wire it up through a relay or a flasher that you mentioned.

grunge311 · 08-31-2005, 09:10 AM

If and when you do this can you please post your progress w/pics? I would consider doing this if its not to involved and there are some decent "instructions"

rjspitz · 08-31-2005, 09:38 AM

This is the route I took. Haven't installed them yet, still contemplating remaking them with a jig to keep the dots in a straight line.
Side view mirror turn signals

Justintoxicated · 09-01-2005, 01:20 PM

Use an LM317T to regulate the current to your LED's for real cheap, and use a relay. Yo could use a resistor but I would not recomend using resistors as the current in your truck will vary on off, has power spikes etc. Unless your planing to udnerdrive the LEDs?

Boone-Titan · 09-01-2005, 06:04 PM

Quote:

Originally Posted by Justintoxicated

Use an LM317T to regulate the current to your LED's for real cheap, and use a relay. Yo could use a resistor but I would not recomend using resistors as the current in your truck will vary on off, has power spikes etc. Unless your planing to udnerdrive the LEDs?

I have several LEDs in my interior and use resistors to limit the current with no problems at all. Voltage fluctuations and spikes are typically below 1.5V and will not effect the LED. If calculated correctly, the resistor can be sized to lower/ adjust the intensity of the LEDs. The most important thing to note when wiring LEDs is that polarity matters. You must know what is the positive and whats ground and hook these to the LED cathodes (wires) a certain way. Have you ever noticed that the "wires" on a LED are slightly different lenghts? This is why. Lastly, If you do not size the resistor correctly and over drive the LED you will significantly shorten it's life span. Done correctly, the LED should burn non-stop for say ~50 years.

Justintoxicated · 09-02-2005, 03:03 PM

Boone, no offense but this is NOT the best way to do it. Voltage changes are typicaly more than 1.5V truck off is a 12-12.8 truck on is up to 14.4 spikes may be slightly more.

Will using a resistor and underdrivnig the LED work Correctly ? Yes...Is the the best way? No, is LM31T the best way? No but it is WAY better than simply using a resistor.

You can add as many LED's as you like the LM317T without worrying too much about it, as long as you stay under the Trucks Max Voltage, and within the LM317T 's specifications. You can still adjus the brightness level with the LM317T also, but adjusting the resistor value.

Basicaly with a resistor only you do not have any overvoltage protection with the LM317T you do.

rdfeatherstone · 09-03-2005, 02:12 AM

Thanks, one and all.

Ralph