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tbird88
01-22-2006, 01:06 PM
I put some of those LEDs from AutoZoo in my tailights but they blink too fast. Do I need some kind of resitor inline? Should I get the GM LEDs instead?

'bird

MSG419
01-22-2006, 03:02 PM
A friend of mine tried these in his Explorer and found the same problem and they also didn't light up very brightly.

I know the LED boards in the rear trunk lights have two resistors on the board - I just took a broken light apart to see what was inside.

Also any of the LED 3rd brake lights I've seen have resistors.

Maybe someone with electronic know-how could give some input here. Maybe 12v to bulb needs to be reduced? Think of what happens when one turn signal bulb is out - the remaining one blinks faster.

Good Luck.
Mark
'93 SC
'95 SC

tbird88
01-22-2006, 03:33 PM
I'm probably gonna cruise over to Radio Shack and get a solid-state variable resistor and put it inline with the lights. That way, I can adjust the speed. The solid-state will keep down any problems with overheating of the wires etc.

'bird

Mike8675309
01-22-2006, 04:07 PM
It depends on now they are flashing the LED. If they are using a simple 555 timer, changing the resistor can change the time.

Changing the voltage powering the circuit might change the time.

Adding a resistor between the LED driver and the LED itself won't due jack but make the LED less bright.

If they are using Pulse Width Modulation to flash the LED, good luck. There is a set resistor somewhere there, but there could be a couple you need to change.

seawalkersee
01-22-2006, 04:34 PM
Tail lights? Or turn signals? What are you planning THIS time Wynn?

Chris

tbird88
01-22-2006, 04:39 PM
Adding a resistor between the LED driver and the LED itself won't due jack but make the LED less bright.
Hmm, excellent point! I saw some flashers on the web but they were like $40 or so.

By the way, whenever my lights are off but the ignition is on the tailights glow just the tiniest bit. Think there's a bad ground somewhere?

Either I'm gonna waltz into Radio Shack hollerin' gimme-a-Pulse-timer-Width-555-Modulation-voltage-resistor or else just put my original bulbs back in.

'bird

tbird88
01-22-2006, 05:03 PM
Tail lights? Or turn signals? What are you planning THIS time Wynn?

Chris
daddgummit...I keep sayin' tailights but I meant rear turn signals. They go blinkyblinky faster than Manny's heartbeat when he sees a cowgirl.

headed to radio Shack!

'bird

Mike8675309
01-22-2006, 05:22 PM
Turn signal flashing faster is something different. This faster flashing is part of a flasher circuit used to tell you that you have a bulb burned out. LED's put less load on the circuit so they make the flasher think the bulb is burnt out.

Try this link for info on a possible work around:
http://www.stu-offroad.com/electrical/led1/led-3.htm

This link mentions a load resistor to go in line At 6ohms and 50 watts, yes she'll get hot.
http://www.ledtronics.com/ds/aut3157/

Note I found references to electronic flashers will also resolve the issue and should be found at many auto parts stores.

Scott Long
01-22-2006, 05:27 PM
I have them in the tail lights of my 92 SC and they make the blinker flash faster. Plus instead of the whole tail lamp lighting up, now they only light up a little circle in the center. Its different but I don't know if I like them. Jen drives the car and it doesn't seem to bother her.

tbird88
01-22-2006, 07:44 PM
Turn signal flashing faster is something different. This faster flashing is part of a flasher circuit used to tell you that you have a bulb burned out. LED's put less load on the circuit so they make the flasher think the bulb is burnt out.

Try this link for info on a possible work around:
http://www.stu-offroad.com/electrical/led1/led-3.htm

This link mentions a load resistor to go in line At 6ohms and 50 watts, yes she'll get hot.
http://www.ledtronics.com/ds/aut3157/

Note I found references to electronic flashers will also resolve the issue and should be found at many auto parts stores.Yep, that's what I meant by BLINK...you Yank...er...Northerners like to be too dang specific.

Anyways, ppretty much got the 1st part figured out about the load etc. Went to Radio Shack and they don't even have alarm stuff anymore much less a car section. I need a siren for my alarm and they just gave me that blank look.

Checkin' out the Jeep link now.

thanks!

'bird

Gregthespy
01-22-2006, 11:09 PM
I'd just go with an electronic flasher module as it is not affected by the load on the circuit to determine the flash speed but a set flash pace. Plus they last damn near forever, and don't requier spicin' and dicin' your harnesses. Much easier to install too. Most auto parts places sell em or can get em for you.

S_Mazza
01-24-2006, 04:03 PM
Yes, according to the manufacturer, you need a resistor. I think I bought the same ones you did, Wynn, and they are sitting in the box because they flashed way too fast. The resistor that the light manufacturer sells is like $40 and requires splicing, so I decided to go back to the ol' 3157 incandescent. Check the manufacturer's website if there is one.

Mike8675309
01-24-2006, 08:34 PM
The LED lights cause the Flasher, if it is an Electro-Mechanical flasher, to flash fast. This is a design of all flashers, including fully electronic ones so that the driver has an indication of a light bulb failing.

The problem with the electro-mechanical ones is that they measure the NET voltage drop in the circut, and if it rises above a certain setpoint the flasher behaves via a rapid flash.

Since a LED lamp has less voltage drop than a Incandecent lamp (LED lamps are current driven, and often have their own current source that limits their voltage drop) the electro-mechanical flasher thinks the light is burnt out and goes into it's rapid flash mode.

Adding a resistor to the line going to the lights adds a voltage drop that then avoids the fast flash. This also disables the circuits ability to detect if the lamp burns out.

Changing to an electronic flasher eleminates the problem as it uses an IC to measure current flow rather than voltage sensing, so it can tell the draw that occurs when a lamp is burned out vs when all lamps are running.

Thus with an electronic flasher and LED lights, you will still get the sensing ability for a failed lamp.

Electronic flashers are fairly new to be generally available, thus most people still sell in line resistors to deal with the fast flashing on cars.

mannysc
01-24-2006, 10:19 PM
daddgummit...I keep sayin' tailights but I meant rear turn signals. They go blinkyblinky faster than Manny's heartbeat when he sees a cowgirl.


'bird
hey I dont like cowgirls i like cow girls i like big butts like em big an round .like a ect ect ect

mannysc
01-24-2006, 10:19 PM
daddgummit...I keep sayin' tailights but I meant rear turn signals. They go blinkyblinky faster than Manny's heartbeat when he sees a cowgirl.


'bird
hey I dont like cowgirls i like cow girls i like big butts like em big an round .like a ect ect ect