LED conversion questions?!?

[Toxifera]

Hello,
I have a 94' Ranger XLT That I am attempting to do a LED conversion on. It uses 3156 & 3157 bulbs. I purchased the appropriate LED bulbs, but I can't get the 3157 marker/parking lights to illuminate. I can get the brake lights to come on from the same bulb. I had to use resistors in parallel with the turn signals to get them to blink. I tried the same resistors on each of the marker lights but no dice. All the resistors did was get extremely hot. Any advice would be greatly appreciated.

 

[pjtoledo]

if the resistor is getting hot then current is flowing thru it. the whole idea of LEDs is they use much less current then regular filament bulbs.
my guess is something is not wired correctly, possibly backwards.
a parallel circuit increases current flow, series circuits decrease current flow, and divide the voltage between the loads.

 

[pjtoledo]

Hello,
I have a 94' Ranger XLT That I am attempting to do a LED conversion on. It uses 3156 & 3157 bulbs. I purchased the appropriate LED bulbs, but I can't get the 3157 marker/parking lights to illuminate. I can get the brake lights to come on from the same bulb. I had to use resistors in parallel with the turn signals to get them to blink. I tried the same resistors on each of the marker lights but no dice. All the resistors did was get extremely hot. Any advice would be greatly appreciated.

that's because the leds don't use enough current to heat up the blinker do-hickie, the parallel resistor is needed to increase the current flow so the blinker module will heat up and blink. so you are still using the same amount of current, only its mostly being used to heat up the resistor rather than light the LED.
don't they make special blinker modules for the LEDs?

 

[55trucker]

For the turn signals try using a dedicated LED flasher, they have no minimum load necessity which a regular flasher for an incandescent bulb does.

https://www.superbrightleds.com/cat/flashers-load-resistors/

 

[Toxifera]

Hey PJToledo,
Thank you for the reply. The regular 3157 bulbs worked just fine before I changed them. It has something to do with the first circuit in the 3157 LED. The second circuit works just fine. The brake lights come on in the rear when the brake pedal is depressed. Something is amiss with the first circuit, the two amber 3157 LED's in the front and the two rear 3157 LED's wont light up when the headlight switch is pulled in either position.
Hey 55trucker. Thank you for your reply. I placed a 55 watt 6 ohm resistor in parallel with each of the LED's in the rear and all the turn signals light up. Be it a little faster than normal. Before they wouldn't blink or come on at all. I tried the same procedure with all four parking LED's in the front and rear but it seems that the current is just passing through the parallel resistors and not the LED's. I am perplexed. All four LED's couldn't possibly be bad.


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[Toxifera]

I forgot to add that I am definitely working with the correct circuit on the parking lights. I checked for a constant 12 volts present when the headlight switch was pulled.


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[55trucker]

My opinion would be to remove the resistors from where you have installed them for the sake of the turn signals and to purchase the dedicated LED flasher needed. The resistors completely null the amperage saving that the LED's offer you. By using the resistors you're building up heat in the circuit and heat is not your friend.

 

[warrpath4x4]

i had a problem once with LED bulbs that wouldn't turn on. even though not marked on them, there is a + and - side of the bulb, turned them and they lit up just fine. that was with the push in style dash lights though.

 

[Curious Hound]

there is a + and - side of the bulb

That is because LED's are "diodes" (not bulbs). A diode is an electronic device which only allows current flow in one direction. Polarity (the "+" and "-" of a DC device) must be observed for proper operation.

I would also echo 55trucker's advice that you get rid of the resistors you have installed and use the proper LED-friendly flasher unit.