need to find out the schematics for an 04 mastiff. What color is what wire? Trying to wire new hand controls 96 up harley style and buttons.
You will have to rewire the entire bike to do HD hand controls on an 04.
The stock hand controls run a negative low voltage control through the EHC.
The HD controls are high current controls, need heavier wire, and need wired differently. Best to pull the entire BDM harness and EHC out of the bike and start from scratch.
I can Email you the 2004 wiring diagram later today.