99f4 aftermarket tail light wiring..
 

Can anyone help? I have a 99 f4 and I'm trying to figure out the proper way to wire it with the resistors.. Any help or suggestions are greatly appreciated!!!

Normally you will attach one end of the resistor to the hot wire and the other to the ground, another easy way to use led lights is to purchase a new relay that is designed for leds, they can be had for between $10 and $20. You will never have to worry about wiring in resistors, if you choose to swap more lights to leds you wont have to wire in more resistors, and it will be a cleaner install without them.

no..... normally you wire the resistors in series with the LED, not to ground, for indicators.


on a tail light you shouldn't need any resistors though.

Okay, so now I have it so that the the tail light works, left and right signal also work.. When I I hold down the brake it gets a very little bit brighter. Any suggestions or advice?? Thanks...

you don't want a resistor on the brake lamp. if you fitted one then remove it.

The resistor makes the flasher relay believe its receiving less power (doesn't flash as fast). There might be a resistor to adapt the LED turn signals to 12V already integrated into the system you have. But the extra resistors are to imitate power dissipation of a bulb. So this resistor must be connected parallel to the LED turn signals, to work properly and efficiently. Thus the video demonstrating how to insert a resistor in parallel with the LED and not in series.

Personally I'd use a no-load flasher because I don't run the risk of having the resistor overheat and melt any cables or anything else heat sensitive. Additionally the no-load flasher will accomplish the same thing as the resistor. Something like this should do it and allow you to not alter the OEM wiring harnes further.

The relay doesn't know what power it's getting. It works on a thermal cycle. The amount of heat is a function of the load. LEDs are a lower load so generate less heat in the relay, hence the slower flash rate. Same thing happens if you blow a bulb, or disconnect an indicator.


The resistors increase the load on the relay, creating more heat, and normalising the cycle.


As you say, a relay specifically for LED indicators is a much better solution.

Okay, so everything works and is looking great except when I apply the brakes I get very little response from the tail light. Thanks for all the help guys!!