I'm installing Shock Racing LED turn signals (15-leds) on a 96 gs.  I've installed an electronic relay, but I still need to install a couple of resistors in the back.

From what I gather, my two choices are: 10ohm 10watt resistors, or 8ohm 20watt resistors.  Which would be better for my setup?

Note: I am only going to be installing resistors on the back turn signals.

Thanks

I'm curious, why do you need resistors if you have an electronic relay?  I would think either of those resistors you are planning on using will work, in fact, may be overkill. 

Quote from: Paulcet on August 22, 2008, 03:40:07 PM
I'm curious, why do you need resistors if you have an electronic relay?  I would think either of those resistors you are planning on using will work, in fact, may be overkill. 

I guess because there are two issues with led signals.
1. The standard relay will not work without sufficient load, which can be fixed by using an electronic relay.
2. The indicator light, being wired to both side signals, will cause all four to flash unless the resistance of the bulbs is significantly less than the indicator light, which is not true of the LEDs.
In other words, if you leave the standard indicator lamp connected, all four will flash even though you have the electronic relay.
If you get the right size resistors (and it doesn't matter whether they're on front or back) you can get the whole setup to work with the standard relay.
If you disconnect the indicator light (maybe replace it with two LEDs) and use an electronic relay, you won't need the resistors.
For further info search for: "amazing new custom flashers"

Ah yes, the indicator light.  Forgot about that.

By my calculations, the 10 ohm resistor will be dissipating over 18 watts.  The 8 ohm would be 22.3 watts.  Since they are flashing, you can get away with either one probably.  But that's pretty warm.  I'd go with the LED indicator myself.

Actually, my problem was that the turn signals were very dim, and they would blink very slowly.  It was almost as if they weren't getting enough power.  Removing the indicator light did allow the left and right to flash independently, but did not change the brightness.  The electronic relay was also not making the "tick" sound that it normally makes when in use.  I also tried using an led indicator, but that didn't make a difference.  Wiring in two 10ohm 10 watt resistors in the back fixed the problem.

However, I'm still curious as to why the lights were so dim originally and why the electronic relay wasn't working properly... even with the indicator light removed. 

Any ideas?

bumpzilla

I just got everything working properly yesterday. What I had to use was the electronic resistor, load balancer, and diode. Works like a charm now! Just gotta pick up another light for the high beams because I broke a light fidgeting with it. Then I am never touching the lights again. What a PITA! The load balancer is about $20 and the diode $6.

Mary s.

It would help to know how you wired in this resistor. Have you seen the simplified turn signal schematic from the FAQ on LEDs?



If the relay is completely electronic, you would hear no sound at all. The "ticking" sound occurs when the mechanical contacts of a relay stike each other, closing the electrical circuit.

Another version of an electronic relay uses a electro-mechanical relay that is controlled by solid state devices. Those type are quieter than the two-pin type.

Electrical modifications are difficult when you don't have understanding of how circuits work. A vicious cycle of "Cut, tape, splice, test, cuss, recut, try this, cuss more, blame everyone else, tape, splice, repeat.." seems to be common. 

More data please...

I just found your original post so the answer to my first question is "Yes".

Does it make sense to you? It is okay to not understand schematics or wiring diagrams.
That is why I made the simplified version that eliminates everything except the pertinant circuit.

I wired the resistors in parallel between the two rear turn signals.  Just connected them between the positive and negative wires, one per turn signal. 

I was able to get it working fine...

The part I don't understand is why the lights are dim without resistors even without the indicator bulb...   people are saying that without the resistors and just the use of the electronic relay, it should work fine.

Quote from: facepants on August 24, 2008, 02:41:30 PM
I wired the resistors in parallel between the two rear turn signals.  Just connected them between the positive and negative wires, one per turn signal. 

I was able to get it working fine...

Using the ASCII  method of schematic representation...you did this...??

(Voltage source)--------->>------+LED------->>-----------(chassis/ground)
                                           |--Resistor--|

Is this correct?

Quote
The part I don't understand is why the lights are dim without resistors even without the indicator bulb...

That doesn't make sense unless there was a poor connection causing a severe voltage/current drop to them.

What were the values of the resistors?

Quote from: starwalt on August 24, 2008, 04:55:36 PM
Using the ASCII  method of schematic representation...you did this...??

(Voltage source)--------->>------+LED------->>-----------(chassis/ground)
                                           |--Resistor--|

Is this correct?

Yeah, thats what i did.

Quote
The part I don't understand is why the lights are dim without resistors even without the indicator bulb...

That doesn't make sense unless there was a poor connection causing a severe voltage/current drop to them.

What were the values of the resistors?

The resistors are 10 ohm 10 watt..

Thanks

That helped some, but the final bit of data will be how much current the LEDs pulls alone. At that point I could provide a proper analysis.

Most LEDs draw in the milliamperage range. 30 - 75 mA.
Most lamps draw AMPS.

By adding the resistors you shunt some current around the LEDs, in this case if the resistor was in the circuit by itself, about 1.2A. This would make the combined circuit look more like the original load of the lamp.

Now this totally defeats a selling point of using LEDs, lower power consumption/load on the system.

You've (rhetorically speaking) just traded where you use the electricity and not how much you use. In fact this system wastes electricity by heating up the resistor. That's why a 10W is used. Anything less would just burn the resistor and it would open up leading to the original problem.

Interesting. LEDs have a cool factor but again I say it is not worth the effort.

If I were selling an LED mod kit for a GS then that would be a different thing altogether.    I would say everyone should buy and "upgrade" to LEDs.

Unfortunately I don't have a meter, so I can't check on the exact draw, but they're shock racing turn signals with 15 LEDs in each signal... maybe that'll give you a rough idea.

Am I correct in assuming that the problem is that the electronic flasher relay I purchased is not completely electronic?  Which is why, without the resistors, it doesn't detect enough load to activate the flashing mechanism to make the lights flash and also cause the "tick" sound?

Quote from: facepants on August 25, 2008, 03:48:48 PM...Am I correct in assuming that the problem is that the electronic flasher relay I purchased is not completely electronic?  Which is why, without the resistors, it doesn't detect enough load to activate the flashing mechanism to make the lights flash and also cause the "tick" sound?

It depends on the device. I just bought two from an autoparts store and have opened them up. I plan to buy more but chopping up a $15 relay for everyone else's education is a little tough on the project bank.

In the purest sense of the term, all of them are electronic. They all may not use semiconductors and ICs to do the job though.

The two pin type can be be either RLC (resisitor, inductor, capacitor - "passive electronics") or a bimetal type (resistive wire heats up and causes a contact plate to warp making a "tink" sound when the contacts close).

I have seen the term electronic used for the RLC type. They all tend to be load dependant because the rapid flasher feature is used to indicate an open turn signal lamp.

Again, I plan to do a page/post on the subject but that is another time sink I don't have at the moment.