View Full Version : LED Tail Lights, Limp-Home Fix!

03-01-2011, 10:40 PM
I decided to install LED tail light bulbs in my Spyder and discovered the Limp-Home Mode. I seen the issue mentioned on here and have not seen anyone say about how to properly resolve this.

I found from the schematics that only light bulbs brake circuit is monitored by the VCM. I played around with resistor values until I found the one that will allow the Limp-Home to be disabled with the bulbs working but will trip if I unplug the bulbs.

I just wired the 3.3k ohm resistor to the tail light plug on the Gray wire in the middle and to the black ground wire.

The resistor value was much higher that I expected to stop Fault Condition at Startup. I originally thought the bulb monitoring circuit was designed for was to monitor a bulb blown condition, not to be a load test or current monitor. This was not the case, the system does a resistance check and needs one functioning brake bulb to not go into limp home mode.

You NEED to use a 6 Ohm power resistor get a 50 watt or larger one so it runs a bit cooler. Mount away from any plastic or wires with screws as this resistor will get very hot if you hold the brake on at a stop for very long.