Since my big mods won't be in for a while, damn Japan is far away, I have been doing a bunch of little mods to keep me busy. I am about 80% of the way through upgrading all the lighting on the car. So far I have changed the dome light, reverse lights, license plate lights and trunk light to LED.
I am still waiting on my LED rear signal lights and switchback LED for the fronts. One of the problems with LED lights in modern cars is they cause "hyper flashing" because they don't pull enough juice to let the system know they are on. This makes the car think there is a bulb out and the "hyper flash" is to make you aware there is a bulb out.
You have a few options on how to handle this. One is you can let it hyper flash, it doesn't hurt anything. However that is pretty annoying looking. The other option is to use resistors. You wire these at each bulb and they fix the issue. The issue with them is you need to splice wires and find a place to mount them, not on plastic. Since the resistors run a little warm it is advised to mount them to metal. The wiring is a snap, you are basically just connecting the two wires or bridging them.
The way I chose to go with was to replace the flasher relay with one designed to eliminate the hyper flash. The only drawback to this method is that it will never hyper flash so you won't know if you have a bulb out. I am not too worried about it, I figure I will just do a walk around with the flashers on every once and a while.
This was not too hard, except my fat ass and big hands made the job "challenging". After you pull off the panel under the steering wheel you need to get under the wheel on your back and reach up under the dash to get to the relay. If you are on your back the relay is to the right of the steering column.
It is attached via a clip to a metal mount. You need to get the flasher off the clip or pull the clip out. Once that is done, easier said than done, you just unplug the relay from the harness and plug the new one in. Then swap the clip from the old one to the new one and wedge yourself back under the wheel and stick it back where the old one was. I suggest you find a small friend with small hands, or even a child, to help. If that is not available then at least get a pair of mechanic gloves to avoid the result below.
Source for Location: EmilGH from FT86Club.com