LED Issues

[Odis]

I bet this has been discussed, but I have looked and looked and can't find the answer.

I just finished restoring my dad's 82 GMC and had the body shop install all LED lights, everything.

At first all of the lights worked, but the blinkers were super slow and they didn't work at all with the lights on. I talked to my local mechanic and he said to replace the blinker relay with an LED relay.

Did that and no blinkers at all, even after I put the original relay back in. But, the hazard lights work with the lights off, but not on.

Please help! I have a beautiful truck and want to drive it!

 

[Jgonick]

My thought is still the relays. LED (electronic) relays terminals can be backwards to what is needed-causing them not to work.

Link to video explaining

Another LINK that explains and suggestion on relay-even though its a jeep

Also something else to watch out for-
LED in front side markers can be problematic- those receive current from two different directions depending whether headlights/parking light are on or not- LED (light emitting diode) Diodes only let current go one direction unless its been modified somehow

 

[TotalyHucked]

The flasher relay is not enough, I had to wire in 50ohm resistors at each tail light and each front marker light. That fixed all my weirdness and has been working great for 4yrs and nearly 50k miles

 

[Jgonick]

I had to wire in 50ohm resistors

LEDs have a much lower resistance than incandescent light bulbs. By wiring in the extra resistors you are basically putting the resistance of the circuit back to where it was with the incandescent bulbs.

Using resistors is another good way to approach the problem. (LEDs with an electronic relay will use less power-but for most people that doesn't matter.) Only downside is if you ever put incandescent bulbs back in instead of LEDs, the circuit could possibly have too much resistance.

 

[gmbellew]

I plan to stick with incandescent bulbs for brakes/blinkers because of these sorts of issues. I just don't see the huge upside with LED in these uses compared to the obvious advantages in forward lighting, reverse lights, the instrument panel, etc.