If anyone is having any issues with installing LED tail lights, or LED turn signals or any aftermarket LEDs in general you may run into an issue with your lighting control module. This may have been discussed already but I just found this out and wanted to make everyone aware. Lighting control modules are the newer style of turn signal flasher. 90's model trucks took EP29's and whatever else but newer model trucks in the 2000's take whats called a Lighting Control Module. Tridon sells them through Advance Auto. Apparently these LCM's control daytime running lights, brake lights and turn signals also. The Tridon LM487 is the most common on General Motors trucks and the LM449 is most common on Toyotas. The LM487 and LM449 are LED compatible whereas the factory LCM is not. Just a little FYI! Hope this helps someone! It helped me. I talked to the product manager at Novita Technologies Inc, who manufactures the Tridon flashers and he gave me the info.